Well one thing I can say for sure is that you mustn't be disappointed with yourself if the first few months of your lessons involve doing the same things over and over and over again.
Riding a horse correctly involves doing lots of things at once, and it will take some time to develop the muscle memory which will eventually allow you to do the following: keep your heels down, use your various aids (feet, legs, body weight, arms, voice, etc), keep a steady feel on the reins without going too slack or too strong, keep your legs from swinging around, keep yourself from slamming down into the saddle during posting trot and the canter, and some other things that I can't think of off the top of my head. There's a lot to do at once, and it will take some time to get it all down pat, but as they say, practice makes perfect!