You might want to check out
last year's rules. The rules change from year to year... but not so much that reading the old rules won't help understand the new ones.
You will want to know something about the batteries, speed controllers and motors in the Kit of Parts. You will find some information
here and some great
seminars and lectures both recorded and in powerpoint format here.
Here's one that Al, who posted above, did. You could do far, far worse than to take advice from Al!
Jason