I had mine installed for me and now that I taken it out my interior looks all hacked up. It mounts before the speaker and when I get a minute I'll run out and get some picks of where the holes are cut into the panels.
It rests on top of the trim. The hole on the top is where the metal part of the light bar goes in. The bottom 2 small holes are where you will screw in the studs. They go through the light bar and into the body.