Settle down

(you're yelling)..
Get into the little 172 practice practice practice landing and pattern work. Mean time, check out the learning center ( or better yet, do some real research) and study up like you're taking a real ground school course.
It's not much fun (or won't do you much good) to just jump into long, ATC controlled flights and try to use the GPS until you understand the big picture. You should already know on your own (because you've checked the weather) which runway you'll be assigned and have long since loaded the GPS approach for that runway. But unless it's real IFR weather, you'll just hand fly the approach anyway. Do you really enjoy having the GPS and auto-pilot do the flying ?
I'm not the biggest fan of the FSX built-in lessons.. But if you are completely new to flying, it will help you grasp all the fundementals..