Hook one of your other speakers to channel 1. Hook another to channel 2 and the other to channel 4 (channel 3 is already connected).
Hook your sub bridged across channels 5 and 6 [use (+) of channel 5 and (-) of channel 6 and leave other two terminals unconnected].
Ignore the red/black wire hanging by the speaker for now. (tape the bare wires off if you want). I suspect it is "leftover" factory wiring.
Pay attention to which (+) speaker terminal is connected to the wire with the stripe so you can get the polarity right at the amp.
Once everything is connected use the HU balance or fader controls to see if you got the front-rear and left-right channels correct. If not, then swap the RCAs at the amp input as needed (but leave the sub input alone)
Hook your sub bridged across channels 5 and 6 [use (+) of channel 5 and (-) of channel 6 and leave other two terminals unconnected].
Ignore the red/black wire hanging by the speaker for now. (tape the bare wires off if you want). I suspect it is "leftover" factory wiring.
Pay attention to which (+) speaker terminal is connected to the wire with the stripe so you can get the polarity right at the amp.
Once everything is connected use the HU balance or fader controls to see if you got the front-rear and left-right channels correct. If not, then swap the RCAs at the amp input as needed (but leave the sub input alone)