2015 Lincoln mkz help with wiring a backup camera

I brought a rearview mirror dash cam. It came with a camera i can mount to the trunk area. There is a red wire that i need to wire into the backup light or reverse light. I don't know much about wiring, but once i get to that area which wire do i connect it to? Is there a certain color pattern? I took it to a installation shop and they said 200.00 bucks to install it. I can pretty much do it all but i just dont know which to connect it to. Please help. I attached a picture of the camera setup