Trailer Electrical - Hooking Up '00 Rover

[slycat67]

Need some advice on hooking up electrical on my rover, so I can tow a boat.

My manual is less than clear regarding how to hook up the electrical for a trailer.

My Questions:
1) Manual says to hook up electrical to BOTH tail lights. HOWEVER, when I get inside the pannel, there appears to be only one hook-up, which is located on the passenger side tail light. There is a small white receptical that I'm assuming is the hook up. Am I missing something?

2) There are two hole plate covers in my bumper, the manual says to remove both of them. Why? In my experience, I've only used one such spot to attach the trailer electrical to a truck. Is one for electrical and the other brakes possibly?

3) Does anyone have a recommendation on parts I could purchase, and where? Local Kragen Automotive doesn't seem to have what I need.