i have 2 rockford 10" p2's

and i just upgraded to jl audio 500/1 and the guy i bought it off of told me to put my positive and negatives together and have one positive and one negative on the amp. well i cant even turn the music up loud at all or my subs start cracking. is four ohm where i dont have my positives and negatives together and each wire has its own port? im hoping this will fix the problem.