There’s an entry point on each side of the trunk space from rear for your back up camera, audio needs, and etc. Have patience though. If you have an audio plug you can sit it in the hole and pull it through from the backseat. Enjoy.
I will when I have time, it’s easy to spot. I’m tall so I had to lean in a little bit. If your car is in the sun it will show better. On the inside of the car, it’s on the corner of the rear seats on the side, about shoulder height sitting down.