I used the existing ARB plug and disassembled the 12v male socket plug end, and replaced it with the PP connectors. It's fairly obvious once you open up the socket which wire is which, but as I recall the positive wire runs to the metal tip at the end of the plug and the negative wire joins the side contacts that touch the outside circumference of the female socket.
Making this change is a good move. I fiddled with different 12v sockets and wires for for months trying to solve various problems before changing to the Powerpoles. I haven't given it a single thought since I made the change.
1976 FJ40 - green and mostly stock
1996 FZJ80 - not so stock