My pointers on how to successfully launch your first liquid fueled rocket:
In the VAB, make sure that you are using rocket fuel tanks, not the liquid fuel fuselages that you get with the plane parts. The liquid fuel fuselages don't work for rocket engines because they don't have any oxidizer, and rocket engines need that since they do not have air intakes. To check if your fuel tank has oxidizer, right-click on it. If you just see one green bar labeled liquid fuel, you are using the wrong fuel tank. Swap it out with another that does have oxidizer. If you see two green bars, one liquid fuel and one oxidizer, then you're all good to go. One very important thing to do before launch is to look at your staging, the bar on the bottom-right with orange labels. Make sure that your engine does not fire the same time as your separator (if you have one on the rocket) or your parachute (which I'm assuming you do have, if not just stick one at the top and pretend it was there all along). Drag the engine, separator, and parachute icons to separate levels, and to add or remove a level, just use the + and - button, although I assume you already know this. Now press launch.
Pilot kerbals (Like Jeb) have stability control by default since they're pilots. They help you keep the rocket pointing where you last turned it with w, a, s, and d. To turn this feature on, you have to press t on the keyboard. A light will light up on the top right side of the ball at the bottom.
Next thing you want to do is press z to throttle up to max. This is what I recommend for beginners to launch at. If you want to change your throttle to be somewhere in between max and off, you can use ctrl and shift to raise and lower the throttle, respectively.
Lastly, press space to take off! You also use space to activate the next stage, so when your liquid fuel has run out, press space (if you have a separator) to separate the capsule and rocket. If you have your separator and parachutes on different stages, make sure not to forget to press space again to release the parachute. Don't worry if the parachute doesn't come out immediately, you have to be going slower than about 255 meters per second, and you have to be at a low altitude. Also don't worry if the parachute doesn't open all the way, it will open completely when you are closer to the ground. That's pretty much it. It is very important to remember, however, that if you are going too fast, the parachute will never open, and you will crash into the ground. Make sure that your reentry path is always sloped and long, not straight down.
Good luck and you will love this game!