As the wiring goes direct to the bolbs, and not a printed circuit bord, it's easy to work out which wiring is for which light. The only thing to watch is that you get the earth and feed wires right. Just follow the wiring from the original lights, the earth will not go too fare befor bolting to the body. The only small bit of advice I can give is to use 7 core (trailer lighting) cable to run up from the bumper lights to the rear body lights. This is just to make it easier to do the physical pushing the wire through, and so it's easier to see which wire is wich at each end, as the wires are 7 diffrent coulours. You can of course use the correct (for a trailer) coulour codes, which will make any later work a bit easier.