That's okay, I'll pick up fro where Aurion ZR6 can't. With the wire that goes to your reverse light, that is the +12v line, and the ground is obviously just that. Connect them as such. With the other one you have there (the RCA), the conductor (the centre pin) connects to the red wire on the head unit end, and the shield (outer ring) connects to the grey wire. You can either cut the connector off and do it that way, or buy a female RCA and connect from that. Something like this will do the trick (Jaycar link).