Zizzle,
First off, stop using the demo. A proper KSP package isn't expensive.
As a newbie to another, be sure and check out what a mod called mechjeb can do. Sooner or later, you will hit something called the (grind)? mechjeb will help with that. Note, many purists (Play stock game only) will call that a cheat, but most of the real life space stuff is mostly handled by computors anyway. Besides, no one is twisting your arm to use the mod.
Sooner or later you will find mechjeb is exactly what you want/need. Stop by the RCSbuildAid thread as well. <- Probably wont need that before mid to late game, but good to have around.
Note: None of what I suggest here helps with rocket design. Kinda on your own with that. But then, anything that tells you something about DeltaV is a good idea to have around.