Jenses VM9312 w/ Subwoofer Install

I have the Jensen VM9312 7" Touchscreen DVD player. I attempted to hook up by Rockford Fosgate 2000 Watt Dual Chanel Punch Series Amp to push two 12: Audiobahns. The Amp has One Red One White RCA input same as most do. the headunit has one 1 red/white front,1 red/white rear, and a green subwoofer output. No natter how i connect the RCA's icannot get the subs to bump correctly. i converted the 2 rca From the amo into one male end and plugged it into the subwoofer input but i got nothing. i then decided to use a line cnverter and convert one left and one right speaker into the RCA but i can only get one sub at bump at a time. Soon as i put my pioneer headunit in...it works great i just cant get the Jensens setting correct!!!