I know im going to sound dumb butTwo days ago someone gave me an alpine MRP-f320 and an Rockford fosgate P2 10" in a sealed Q logic box.I plan on installing this just for about a month before i start ordering for my new system. On the amp it has settings for channel 1/2,channel 3/4 and subwoofer.It also has RCA inputs for channels 1-4 but not for subwofer.It has outputs for 1-4 and sub. Im only going to hook it up to a sub and nothing else.I have an eclipse head unit with 3 5v outputs (front,rear,nonfading).How do i hook the sub to the amp properly.