mate i've never used one of these b4 but let me c if i can help you
ok ur factory HU is old and usually dont have rca preout or remote wire. so u have to use ur speaker wires and put it thru a convertor. other side of the convertor should be rca out and now u can connect rcas to ur amp and drive the sub. some amp, or most modern amps these days allow for speaker wire input so u dont even need this convertor and just plug speaker wires straight to the amp, check ur amp first
so from the picture, the 4 wires connects to the 4 speaker wires on ur HU