Snark

...Except that now that you've posted your screenshot, it seems likely that it is piloting.
Why do I say that?  Well, since you're running KER and have helpfully included the readout there, it looks like you have something like 8.5 km/s of dV.  That should be comfortably enough to do a Mun landing and return.   A typical dV budget for a Mun mission looks like:  About 3400 m/s to get to LKO, then about 850 m/s to get to Mun, then something like 250 m/s to slow to orbit, then 700 m/s to land, another 700 m/s to take off, another 250 m/s to go home.  So, a bit over 6 km/s altogether.  With 8.5 km/s on your ship, you should be able to do a Mun mission with over 2 km / s of dV to spare.
So... something's off, here.
You're wasting a bit more dV to aerodynamic drag than you need to, because you're using the "blunt" adapter between your 2.5m stack and your 1.25m stack; I'd recommend using the tapered adapter for better streamlining.  However, that's a pretty minor thing and can't explain what your troubles are.  If you can't even get that ship to Kerbin orbit, let alone the Mun, then there's something amiss.
Can you describe exactly how you get that ship to orbit?  What do you mean by a "normal" orbit, and when you say "couldn't", what do you mean?  Do you mean you run out of fuel when you're still on a suborbital trajectory?
Here are a few specific questions that will help us get a clearer picture:
When your ship hits 10 km altitude, how fast are you going, and how many degrees from the vertical are you? When your Kickback SRBs burn out, how fast are you going, what's your altitude, and how many degrees from the vertical are you? Describe what you do to put yourself in orbit.  You launch off the pad and then what?  Step by step. More questions may follow later, but those will suffice for now to get the ball rolling. 
 

Not that I know of.
It's also worth noting that unless you play with the difficulty settings cranked way up, there's basically no practical / economic reason to recover stages, in a stock career game.  The cost of a spent SRB booster is trivial compared with the payoff from contracts, and the real in-game currency is your (player's) time, not .  If you save yourself five minutes by saying "eh, to heck with it, I'll just discard the stages" rather than trying to recover them, and instead apply those five minutes towards some contract... the payoff from the contract is hugely bigger than the time spent recovering the stages.
Just because it's not economically needed doesn't mean "you shouldn't do it", of course.    As with basically everything in KSP, it all comes down to individual player choice and playstyle:
Some people (like me) find trying to recover stages to be a pointless waste of time that gets in the way of doing other "fun" things, and don't bother with it.  And they have a fun and satisfying KSP experience. Other people find more "realism" in their games (such as stage recovery) to be fun and important.  So they do stage recovery for the fun of it.  And they have a fun and satisfying KSP experience. Other people like running with the difficulty settings cranked up so high that just running a space program without going bankrupt is a big challenge, and even a 1% savings in ship cost really matters.  So they do stage recovery to pick up a few spare pennies that can make the difference between survival and insolvency.  And they have a fun and satisfying KSP experience. So, as with everything:  do what's fun for you. 

The illustrated guide that @Rocket In My Pocket posted above is a good way to set up an initial rendezvous, i.e. for getting within a kilometer or so.
To actually close the distance, you may find this illustrated docking tutorial that I wrote helpful.  You're not docking, but a lot of the same principle applies here.
Yep, you just EVA him across.  You won't be able to switch to his ship until you get within 2.3 km of it.  Once you're close enough, just use [ or ] to switch.
There's no docking involved (stranded kerbals are always in a ship consisting of a single command pod and nothing else, so they never have docking ports on them).

Also, for an explanation of why it doesn't stay stable:  Because you've built a rocket that wants to be pointed the other way around, and you haven't given it anything to steer with.
Note where your CoM is.  It's back near the back of the ship.  That's bad, because ships going through atmosphere really really want to have their CoM in the front.  So your ship wants to be pointed engine-end forwards.  Adding a nosecone might help a little, but I suspect not much; with a CoM in the back, there's not much you can do.
Compounding the problem is that you haven't given the ship any way to steer itself.  Yes, you've got some AV-R8 winglets on there, but you've put them in a location where they can't actually provide any stability or steering authority.  Why?  Again, look at the screenshot.  Look at where the CoM is, and then look at where those winglets are.  They're only very slightly below the CoM.  That means they're of very little use even as passive fins, and they have very little control authority because they just don't have a lever arm to work with.
So, my advice to you would be to do the following:
Put a nosecone on.  It's not enough to solve the problem, but it will make your ship fly a lot more efficiently through air.  Note that you don't need a decoupler or anything-- you can attach the nosecone straight to that big docking port.  The docking port has a "decouple node" option on its menu in flight that will allow you to ditch the cone once you're out of atmosphere. If there's anything you can do to move heavy components higher on the rocket, do so.  For example, put that probe core up top-- it's a full half-ton in a very vertically-compact package, so it's nice and dense; it'll help you a bit for that to be on the front end. Move the control fins down-- waaaaaay down, as far down as you can manage.  The farther down you can put them, the more they will help you.  You want them way behind the CoM.  

Moving to Gameplay Questions.
In general:  Depends on the antenna. Specifically:  All the "direct" stock antennas stack, except the Communotron-16S. In general:  Depends on the antenna. Specifically:  All the "relay" stock antennas stack. Note:  "Stacking" isn't just a binary yes-or-no.  There's also the question of how well do they stack.  Specifically, there's this thing called a "combinability exponent" that determines how powerful the combination is-- in general, it's not linear.  The default combinability exponent for any part that doesn't otherwise specify is 0.75, meaning that if you have N antennas, their combined power will be N0.75.  (The actual formula's a bit more complicated than that, to allow for possibly having different kinds of antennas with different powers.  But if all the antennas involved have the same power as each other, it boils down to that.)
All the stackable stock antennas have a combinability exponent of 0.75, except for the Communotron-16.  That one has an exponent of 1, meaning that it stacks better-- linearly, in fact.  If you have 4 Communotron-16 antennas on a craft, they'll have 4 times the power of a single one.
So, to summarize:
Communotron-16S does not stack. Communotron-16 stacks linearly. Everything else stacks with a combinability exponent of 0.75. You're generally correct, as described above... except you got unlucky and picked the worst possible example, since you mentioned the one single stackable stock antenna that actually doesn't have diminishing returns.   

Hello, and welcome to the forums! 
Seems likely to be caused by a mod.  So, the solution's pretty straightforward-- just establish which mod it is, then go post in that mod's thread to ask for help.
The (relatively) quick way to narrow it down:
Run KSP with no mods installed (i.e. pure stock), verify that the problem doesn't happen.  This means that yes, it's a mod. Install half of your mods (doesn't matter which half).  Whether the problem occurs or not will then tell you which half contains the problem. Take that set of potential culprits, divide it in half, and go back to step 2. Keep repeating steps 2-3, halving the list each time, until you're down to the individual mod that causes the problem. Since the list halves each time, it'll narrow down pretty darn quick even if you had a thousand mods installed.

The RA-15 and RA-100 transmit pretty fast, and do fine against aero forces.  A bit of extra weight, but they work great.
Another possibility is to put multiple Communotron-16S on the craft.  It won't make it transmit any single science result faster... but it means you don't have to wait until transmitting one result before you start transmitting another.  They can transmit simultaneously, and if one antenna is already busy when you go to do another transmission, the game is smart enough to use one of the idle antennas to do it.  Given how long it takes to fall through a gas giant's atmosphere (especially with parachutes), you've got plenty of time.

Thanks, but I've had to go in and snip it out of your post.
I know you meant well, but please don't post large files (such as log files) in the forum itself.  It causes peoples' browsers to lag, it makes forum pages unreadable, and for folks on mobile devices it can lock up their browsers entirely.
Sharing log files is still a good thing to do... just don't put them in the post.  Instead, post the log file to some third-party file sharing site (there are lots of free ones on the internet), and then post a link to it from here.  Thanks!
Anyway:  It's clear that you've got mods installed.  (The fact that you have a ModuleManager.cache file indicates that you have ModuleManager, at least, installed.  I'm guessing you have others, too.)
So, the first thing to do is uninstall all mods completely.  That is, inside your GameData folder, there should be a "Squad" folder (the one that was installed with KSP), and nothing else, not even any empty folders.  Then try running.  Does it work, or does it crash?
If it works then, it means the issue is with one of the mods you have installed, so all you need to do is to narrow it down to which mod is causing the issue. If it doesn't work then, you've got some other issue, but let's cross that bridge when we come to it. Also, incidentally, deleting ModuleManager.cache is a red herring-- don't bother with it, it's not hurting anything.  It's a symptom rather than a cause.  ModuleManager just creates it for performance optimization each time it runs.  The problem you're encountering may have something to do with a malformed config file somewhere that ModuleManager is reading, or it might not have anything to do with ModuleManager at all-- hard to say at this point.
The main thing to do first is to establish whether it's a mod causing your problem, and if so, which one.

I just put a couple of parachutes at the heat-shield end of the ship, set to open at a higher altitude than the other chutes at the other end.  So, those chutes open, which makes the ship flip upside down.  Then I decouple the heat shield, which quickly wafts away because it has a much lower terminal velocity than my 60-ton Eve lander does (even when it has a couple of parachutes open).  Then I open the rest of the parachutes, which flips the ship right-side up again and slows it to safe landing speed.
I've done this too, but I have a lot of trouble getting it to work reliably.  Unless the ship is almost perfectly upside down when I decouple, the darn heat shield always seems to torque around and flip suddenly, smashing my ship and breaking something important (i.e. "anything at all", because if there's one thing an Eve lander isn't carrying, it's anything nonessential).  I always seem to have to use F9 to restore quicksave and try it about a dozen times in a row before I luck into catching the tumble at just the right moment.
But since switching to the parachute-assisted mode, it's nicely smooth and predictable; works like clockwork.  Tap spacebar once, ship flips.  Tap a second time, heat shield goes bye-bye.  Tap a third time, ship reorients for landing.

I routinely use alt+F4 to quit KSP. I do it all the time, it's basically the only way I ever exit the game. And I've never had a problem with it, not once in three years of playing KSP.  I exit this way from KSC view, and from inside KSC buildings such as the VAB.  It's more rare that I'll do it from flight view, mainly because I don't want my current state-of-the-world to be lost since my last save or auto-save, but I've done it plenty of times there, too, with no issues ever.
So I suspect that alt+F4 concerns here are likely to be a red herring.
For the record, I don't make a practice of exiting programs in general via alt+F4, since it's not a good idea.  That's an easy way to get things into an inconsistent state, and can give software a tummyache, depending on how it's written. So to be clear, I'm not advocating alt+F4 as a common general practice. KSP is basically the only program where I do this as a matter of course.
I do it in KSP for two main reasons:
First, the game is designed in a way that I've found to be very alt+F4 tolerant. It stores ships in single monolithic files that are read and written all at once, in momentary bursts, and not touched except when loading or saving, which is brief and synchronous. Ditto the save-game itself. There's no program state that depends on multiple different files that have to have some mutually consistent state. There are no important files that are continuously "streamed", or held open for long periods while the game plays. It's basically alt+F4 proof, as far as I can tell.
The other reason is that KSP has a game design that strongly encourages me to use alt+F4.  I love this game, and I love most of its design... but I gotta say that I've always found it to be incredibly tedious and frustrating to exit. I have to navigate through umpteen menus and mouse clicks, many of which have forced pauses of multiple seconds while the game locks up as it loads stuff.  I'm a generally very patient person, but I've got very little patience for roadblocks to exiting a program.  That needs to be quick, safe, and simple.  I'm happy granting a game (or any software program) all the time it needs to load, but for me there's just no excuse for making it hard to get out. It should be, at most, a single mouse click and a couple of keystrokes away, at all times, with zero waiting. KSP fails miserably in this regard, despite its nice design otherwise.
So, as far as I'm concerned... hello, alt+F4, my friend.
Yep, and that's a good practice.  But for KSP, I think alt+F4 is okay.
I believe not.  That's just a cache file that's designed to improve loading times.  The way the game is written, if the loadmeta file isn't there, the menu is slower to open up (because the game has to rummage through a lot of slow-to-read files), and then creates the loadmeta file for you.  That way, on subsequent executions, the game can just read the loadmeta instead and is a lot faster to pop up the menu.  I believe that the game has a quick/cheap way to know "is this loadmeta up-to-date with the state of the file it's generated from", so that it knows when to re-generate the loadmeta, so I don't think you need to worry about the loadmeta being "corrupt" in some fashion.  However, if there's any concern there at all, just delete the loadmeta files-- they're not needed, the game will re-create them as necessary.

Nope, you've got it exactly right, it's a dumb contract. 
There are worse ones.  "Mine ore from Jool and take it to <anywhere>" is one of my favorites-- it's a priori impossible.  The contract system is notorious for occasionally spitting out "lemons" that are either flat-out impossible, or whose difficulty is way out of proportion to the reward.
Anyway, in your case:  all I could suggest would be, try getting into Duna-stationary orbit just barely east (or west) of the limit of Ike's SoI, and see if that's close enough for the contract to complete.
If it does, great! If it doesn't, it means it's the game's fault for giving you an impossible contract, and I'd say you're well within your rights to just force it complete using the Alt+F12 cheat menu.

Moving to Gameplay Questions.
@capt: scarlet, glad you got it figured out!    If your question is answered, you can mark it as such by clicking the little gray "check mark" button over on the left-hand side of the post you feel is the best answer to your question (in this case, might be your own post where you mention what you discovered).  That'll let other folks know that the question is done and no further assistance is required.

Moving to Technical Support.
As for debugging the source of the problems: just use good ol' process of elimination.  Uninstall half the mods, see if the problem persists. That'll tell you which half contains the problem. Slice in half again and repeat until you've narrowed it down to one mod.
Even if you have a hundred mods installed, that should only take you a few minutes.

Why not just land the tanker right next to the mining base so you don't have to schlep it long distances or up hills?
If you land it within a couple of dozen meters of the mining base, and don't mind installing a mod, KAS pipes & connector ports work great for this sort of thing; the tanker doesn't need wheels at all.
Alternatively, if you land it within a few hundred meters of the mining base, you could have a dedicated "fuel truck":  Orbital tanker has no wheels, it just lands and stays put.  Fuel truck is just a 16-ton or 32-ton LFO tank, sitting on some wheels, with appropriate connector ports.  Fuel truck fills up at the mining base, drives over to the tanker, dumps its load, then repeat as needed until the tanker is full.

By the way, @Ncog Nito, to address the specific things you mentioned in your original post:
Rocket engines use oxidizer, and only oxidizer, to burn their fuel.  They don't (can't) use atmospheric oxygen at all.  When you run them in atmosphere, they use the exact same amount of oxidizer (relative to liquid fuel) as they do if you're running in vacuum. When you are running in an oxygen atmosphere (like Kerbin's), jet engines win over rocket engines, by a lot, for airplane-style flight.  It's simply no contest.  They're hugely more fuel-efficient.  So there's basically no reason to put a rocket engine on your airplane, unless you need it for getting up to altitudes where the jet engines don't work. Note that the Terrier is an especially bad idea for taking off with.  Not all rocket engines are the same.  Some of them work well in atmosphere (and are therefore useful for taking off from the launchpad), but the Terrier isn't.  It's a "vacuum engine" and has horrible efficiency at sea level-- its thrust drops to practically nothing, while still gobbling plenty of fuel. So if your goal is to build a long-range plane that cruises at conventional airplane altitudes... don't use rocket engines.  At all.  The only reason to put rockets on your plane is for higher altitudes (e.g. getting to orbit, or suborbital hops).

You've got the right idea, just haven't carried it far enough.
You want the CoM of the ship to be really close to the heat shield.  As close as you can possibly make it. Sticking airbrakes at the other end is a great idea... but you need lots of them, and they need to be really far back.  The distance from your CoM to the airbrakes needs to be a significantly big multiple of the distance from your CoM to the heat shield. Alternatively, put an inflatable heat shield at each end of your ship.  Another option is to put the inflatable shield on the back end of the ship, like a big heavy parachute.  Then put a smaller heat shield on the ship itself.  
 

Hello, and welcome to the forums! 
Moved this to a thread of its own under Tech Support, since this looks like a problem you're having with your KSP.
Can you be a bit more specific about what your problem is?  For example,
Is the issue that when you go to the VAB, your ships aren't there? Or is it that you just want to find the ship files when you're outside the game, and you don't know where to look? If it's the second one, they're in your KSP folder, under saves/<save game name>/Ships/VAB (or SPH instead of VAB, if you're looking for craft that you made there).

Hello, and welcome to the forums! 
This is mainly a question about how to play the game, so moving it to Gameplay Questions where it's more likely to get answers.
 
I'd say it's because you're near the limit of their range, since the satellites are so far apart.  (Nice screenshots, by the way-- great idea for a post like this, really helps us to see what your problem is.)
The antenna you're using there is the HG-5.  That antenna has a rated antenna power of 5000 km.  That's the range that two of these antennas talking to each other would have.  (You get green lines from them back to KSC because KSC is so enormously more powerful than the HG-5 that it extends the range a lot.)
You do have a few extra antennas, which boosts the range a bit, but not a super large amount (it's nonlinear).  If your two satellites had one HG-5 each, they'd have a max communications range of 5000 km to each other.  With two HG-5's on one satellite, and four on the other, I believe your max range between the two should be a shade under 11,000 km, if I'm doing my math right.
I don't know exactly how far apart your two satellites are, but given that the Mun's orbital altitude above Kerbin is 12,000 km, it looks to me from your screenshot that they're probably 8000ish kilometers apart, which would be on the order of 75% of their max range.  So, not surprising that they're not getting a super-strong signal strength.
If you want to make the signal stronger, you could pile on more antennas, though that's subject to diminishing returns (it's nonlinear).  Best way is to unlock the next step up of relay antennas, the RA-2, which will have plenty of power to communicate to each other from anywhere in Kerbin's SoI.

^ This.  I've used launch clamps with EL and they work great.
^ I had exactly this problem, which is why I used the launch clamps, and they did exactly what I wanted them to.  Solved the problem perfectly.
The reason why stuff flies up in the air is that EL tries to put it right at ground level at a point in the center of the craft, which means the uphill side of the craft is going to be slightly underground, and the game's physics engine interprets this as a "collision" and throws it up in the air.  It's the same reason why, if you build a KAS base with multiple components connected by pipes, they have a tendency to jump up in the air every time you switch to the base.
The solution is to get the ship up off the ground so it's not in contact.  Launch clamps do a great job of this.  For the jumping-KAS-base problem, I solved it by making sure that all my base components were elevated off the ground on landing legs so that the only thing touching the ground is the legs.  I believe this works because legs have some "give" to them and KSP has code in it for detecting the foot's position relative to the ground surface and adjusting accordingly, which stops collisions from happening.
Yes, that's what they are.  The vertical trusswork-looking things with the red thingy at the top.
What do you mean by "don't have those"?  They're really low on the tech tree, and it's practically impossible not to have them if you've progressed any distance in your career.  I'm astonished if you managed to get all the way to the Mun without having unlocked them already.
In any case, if for some reason you don't want to use launch clamps, another idea that occurs to me:  try building craft that have landing legs holding them off the ground, such that the legs are already extended at construction time.  Based on my experience with KAS bases, I suspect (but do not know) that this ought to work, as long as you're not on a slope that's so steep that the uphill legs are buried more deeply than their suspension can travel.
 
Why do you say that?  They work exactly like a decoupler.  Just right-click on the launch clamp and choose "decouple" and bang, there it goes.
That's physically impossible.  They're implemented in a way that they extend down to the ground, however high it happens to be, and are anchored in it.  Can't happen.  (Or at least, I can't imagine it happening... certainly I've never seen it in the game.)
Also, note that you don't have to keep the thing attached to the launch clamps, if you don't want to.  You could just use them as a "construction scaffolding" so that you can build stuff without having it jump in the air.  Build with the clamps, then decouple them and let the newly-constructed thing settle to the ground, then get rid of the clamps.
Citation please?

Hello, and welcome to the forums! 
Yep, it has a way of doing that...
Lots of options!  Depends a lot on your desired play-style.  Different things bug different people.
Some of the things you can do:
Option 1:  Just ignore it.  It's not hurting anything.  The chances are basically zero that it will ever collide with anything.  It's not using up any significant amount of your computer's processing power.  And by default the game won't let it build up more than (IIRC) 250 debris, so it can't increase indefinitely.
The only reason you'd need to clean it up is if it just bugs you that it's there.  That's totally a matter of taste-- it bothers some people, others don't care, others actually kinda like having some junk floating around.
 
Option 2:  Reduce the limit, then just ignore it.  The game has a built-in limit of how many debris it will allow to accumulate before it starts auto-deleting them.  By default, I think it's something like 250.  But that's a game setting, and you can lower it if you like.  So, if you don't mind having some debris, but you just don't want a lot of it, then you could just lower this threshold and then ignore the debris.
 
Option 3:  Use the tracking station for house-cleaning.  Go to the tracking station, then turn on the display of debris (by default it's hidden)-- you can toggle the individual ship types display-or-hide by clicking their icons on that thing at the top center edge of the screen.  Once you've done that, the individual debris objects will show up in the ships list.  Just click on one, then click on the red "Terminate" button down at the bottom.  The game will prompt you "Are you sure?"  Say yes, and poof, gone is that piece of debris.  Repeat for as many debris items as you like.  Once you're done, you can turn off debris display again.
It can be tedious to do this, one by one, if you have a lot of debris.  But it's handy for cleaning up individual ones.  If you've got a lot of debris and just want to do a one-time housecleaning, you could briefly lower your debris limit (to clean out a lot of it in one whack), then move it back up again.
If you use this technique... be careful not to accidentally delete one of your "real" ships!  The game's "delete UI" is poorly designed-- it doesn't give you any clue what you're deleting, whether it's crewed, etc.  You just have to be super careful to click the correct button in the ships list.
 
Option 4:  Play in a way that doesn't generate debris in the first place.  This is a common practice for folks who have a principled stand against leaving debris around.  It's not too hard to do, if you design your ships & missions accordingly.  Ejected booster stages take care of themselves, as long as you take care to eject them while you're still suborbital.  Missions to other moons or planets can design so that they eject stages when they're on a collision course with the target body.  That leaves situations where you're in a stable orbit, and ejecting would lead to persistent debris.  So, either just don't eject in such circumstances (i.e. hang on to the thing-you-want-to-dispose-of until you're suborbital or on a collision course), or else design such stages to have their own small engines and some reserve fuel to deorbit themselves.

Yup, pretty much.  The expansion contracts are always to add new stuff.
Note that it's not just contracts for bases, per se, that seem to get a disproportionate share of cupola love.  It's fairly common to ask for this in orbital station contracts, too.
In my own games, I generally ignore all base-expansion contracts, since I find that expanding surface bases is a hassle (they're inconveniently awkward to dock to, and I'm sufficiently prejudiced against the Klaw that I refuse to use it in my own gameplay for this sort of thing).  Expanding orbital stations is way easier, and just as lucrative, so if I'm going to expand something, it's generally that.
 

Hello, and welcome to the forums! 
Moving to Gameplay Questions, since this is more about "how do I play the game" than "the game appears to be working incorrectly."
The problem is that your rocket's not aerodynamically stable.  I see you've got a good start on it, by putting fins on the back, but your CoM is too low, so the fins aren't getting a good lever arm to work with.  If you can rearrange your rocket so that the heavier parts are up at the top and the lighter parts at the bottom, that would help.
It also looks like you're using 3-fold symmetry; that's been known to be a little flaky with stability sometimes.  Any chance you could go to 4-fold?
Try moving the SRBs as far down as you can (i.e. mount the radial decouplers as low as possible on the central core, then mount the SRBs as low as possible on the decouplers), then add fins to the SRBs (also as low as you can possibly get away with); that could help.
Out of curiosity, what do you have inside that service bay?

Hi, and welcome to the forums! 
Yah, that's basically a fact of life.  Things age, people move on.  The tutorials tend to age.  Perhaps some folks find them useful, but in the three years or so I've been playing, I never really got a lot of use out of them.
On the other hand, the "Gameplay Questions" forum here is great, and I think you'll find that asking specific "how do I do X?" questions here will get you prompt and helpful responses.
I've never used subassemblies much myself; I find the UI unpleasantly clunky, and I can slap together a new ship from scratch so quickly these days that I don't really need subassemblies.  However, there are other folks who use them a lot.  It's all a matter of taste.
To store a subassembly, you need to put your parts tab into "advanced" mode (the little arrow key at top left), then choose the subassembly tab, which will cause a rectangular "drop subassembly here" patch to show up at the bottom.  Then just drag your subassembly and drop it there.
At the top edge of the screen, towards the left side, are three buttons for choosing which UI subset to show.  One's for parts (that's what's displayed by default), one's for crew (i.e. which crew is in which part before you launch), and one's for action groups.
Click the one for action groups, and the parts tab will be replaced by the action groups tab.
Click on the action group you want to tinker with (for example, "Custom01" if you want the action group that activates via the 1 key).  Then click on a part you want to add to that group (for example, a deployable solar panel).  That will cause the action groups tab to list all the potential actions you could do with that part (e.g. extend, retract, toggle, whatever).  Click on the action you want to add to the group, and you'll see it move over to be listed under the group.
Not sure what you mean by that.  May be a design concept, but it's not an explicit functionality in the game, really.
A popular mod, Kerbal Attachment System.
Note that for certain very common terms that are used a lot in the forums (like KAS), you'll see a little dotted line drawn under them.  That means they're a common vocabulary term, and if you mouse over it, you'll get a tooltip telling you what it is.  It's a handy little feature designed specifically for new folks like you, to help you penetrate some of the jargon.
 
If you're playing in career, you can't create maneuver nodes unless you have upgraded Mission Control and the Tracking Station at least once each.  In sandbox, you can make 'em from the get-go, since all buildings are pre-upgraded to the max.
The examples are probably done in sandbox, where every kerbal starts with 5 stars of experience.
In career, all your kerbals start out at level 0.  Getting them to Kerbin orbit will take them to level 1.  Level 2 requires visiting Mun and/or Minmus (you get varying amounts of experience depending on what you do-- simple flyby is the least, orbiting is more than flyby, landing is more than orbit, and planting a flag gets you the max).  To get to level 3 and above, you have to leave Kerbin's SoI.
Probably not.    You might get lucky, but writing a tutorial takes time and effort and it's fairly uncommon for them to be created "on demand".
Generally you'll have the best luck with just posting specific questions here in this forum when there's something you're having trouble figuring out.  (Screenshots really help, in many cases.  You can take a screenshot in-game via F1.  To post a screenshot here, first host your screenshot somewhere like imgur.com.  Then right-click on the image, choose "copy image location", then paste that URL here in the forum and it will automagically get converted into an in-line image.)
You're not the first one to think that.    Like just about everything in KSP, "there's a mod for that".  For example, I seem to recall that there's a mod out there that rejiggers the tech tree to do exactly that-- I think it's called "Better Than Starting Manned".
Mainly just do exactly what you've done here:  post questions to this "Gameplay Questions" forum.  You'll almost always get an answer.  Usually a correct one.  And often an actually helpful one! 

So,  it used to be, pre-1.2, that it worked exactly the way you were expecting:  first drain the center tank, then the outriggers, because of the way the fuel flow rules were set up.
Now, in 1.2, by default, it's the other way around.  Why?  Because now tanks have this new-with-1.2 thing called "flow priority", and the highest-priority tanks are drained first, and by default, the earlier stages are given a higher priority than later stages.  Since your radial tanks are attached by decouplers, they're being interpreted as "earlier stage", which means they get a higher priority and are drained first.
However, it doesn't have to be that way-- if you really want it to be the other way around (i.e. drain the center first), you can make it do that.  Turn on "Advanced Tweakables" in the game options.  Then, whenever you have the right-click menu open for a fuel tank (either in the editor, or in flight), it'll actually show you the fuel flow priority (it's a number)... and you can edit it by clicking little + and - buttons.  So you could make the center drain first by raising its priority higher than the outer tank's, if that's the behavior you want.

This is fairly easy, if you know the secret handshake.    You can do multiple tank transfers concurrently.
Let's say you have one big orange tank full of fuel, and N smaller, identical-to-each-other tanks that are symmetrically arranged and which you need to have identical amounts of fuel in, so that you'll have an even mass distribution.
You can select as many tanks as you want (right click the first one to select, then hold down ALT while right-clicking additional tanks to select them).  Once you have selected the big orange tank and all the little ones, just click the "out" button on the big orange tank.  Presto:  propellant starts concurrently flowing into all the little tanks, symmetrically.
Unfortunately, this is hard, though it seems silly that that's the case.  The stock game doesn't give you any tools to do this; you just have to eyeball it.  Unless you come up with some hacky design trick, like including some small empty tank on your mining vessel that you can use as a "measuring spoon".  Fill up the little tank completely (thus guaranteeing even LF + O), then empty that tank into your target tanks.  Repeat.
^ Same problem as the "equal fuel + oxidizer" issue.  Just have to eyeball it, there's no precise way to do this in stock unless you're using a "measuring spoon".  Annoying, yes.
 
So, to summarize:
Equal amounts in multiple tanks:  yes Equal LF versus O:  no Precise amount transferred:  no