I love this, Vinnie you are great. This game has a lot of weird intricacies to learn, here are a few tips that I think will help you right now:
To get to the moon most efficiently, you want to aim either east or west when you tilt your takeoff. East is best, which is 90 degrees on your navball compass. This will set you up in an orbit on the same plane as the moon.
When you activate stability assist, you need to remember to turn it off 'prograde' mode when you are adjusting your orientation, that is why it keeps dragging you back to facing the ground.
Your fuel/oxidizer imbalance is because you used an aircraft part. Airplane engines use oxygen from the atmosphere, so they don't need oxidizer. It's a little tricky to check for in the build interface but the information is there if you look for it.
Maybe you figure some of this stuff out in the next episode but I hope at least one of these tips is helpful. Keep flying!
Jamsque's comments