+12v from the camera goes to your reverse light, Gnd Wire to a convenient piece of metal, plug RCA into Backup cam input on radio, make sure "reverse" wire on headunit is connected to "+12v reverse signal" and make sure its turned on in the option menu of the radio.
What he said its gravy,i chose an older 08-12 model tailgate handle with integrated camera for looks & ease of install works great,love being able to turn it on at any time which makes checking on your trailor hookup a snap.