Ok, Firstly, don't worry about being new, you will very soon get used to it & we try to think we are quite a friendly buch
With a stock motor and 36 batteries 2 packs should be fine, even if you can't charge between heats you probably have enough capacity.
All heats run in ability order, but there are no classes for mod/std just a 2wd 4wd split (assuming enough numbers otherwise these would be mixed too).
Losi and Associated dominate the numbers in 2wd, but one or two people run different (eg schumacher, tamiya).
Crystals- do you use 40 fm or 27mhz?? although there are more to choose from on 40, its far more popular and you proably need 2 to 3 sets, on 27 you may be ok with just 1 or 2.
Tyres, Schumacher mini spikes in yellow are best for yourself, dont forget when ordering that 2wd use SLIM fronts
Practice- everyone who helps put out the track and pack away can practice before the racing starts, you just put a peg on the board for your crystal and thats it. Racing usually finshes by about 5 -5.30 for a normal club meet.
Hope that helps