Welcome, Eagles! As they said above, start your physical training sooner rather than later. Forget just about everything you know about football that you see on TV on Thursday nights, Saturdays, and Sundays - a whole lot of those rules don't apply down here in high school football. When you do get your hands on a rulebook, READ RULE 2. Then READ IT AGAIN. AND AGAIN. AND AGAIN. AND ANY TIME YOU'VE GOT A FEW SPARE MINUTES, READ SOMETHING IN RULE 2 SOME MORE.
*cough cough* you also might be able to find old rulebooks in pdf form on the interwebs *cough cough*