I've done the install. I don't have the instructions, but I do remember a bit from the install.
I remember the left rear tail light has to be removed, and basically the wire harness connects there. Then when you look under the car in back there's a rubber grommet that gets pushed out and the wire harness runs through there. Then the built in grommet that's on the harness just gets pushed into place where the old grommet used to be. The wiring itself didn't work for a bit though. I had to start the car, hit the brakes until the car actually recognized it.
Let me know if you have any specific questions, I can try to remember. It was over a year or two since I did it.