Wiring lights for headache rack?

Hey guys, I recently picked up a magnum headache rack used, but it doesn't have the wiring harness, and I don't have a 7 pin trailer connector. So far, I've got tail lights, turn signals, and backup lights to work, but I'm running into problems getting the brake lights to work. I'm not the most confident when it comes to wiring, but if anyone could help me figure out what has to go where in order to get brake lights to work, that'd be awesome. I'll have to run back out to see what I've for wired where to get this far haha