i've posted it on here, if you do a search you should find it. I don't think they were to clear on how it is set up though. It was as simple as drilling through the trailer where the studs are in the walls. Sliding a 3" bolt through and putting a nut on the outside so that thee bolt stays in place. Then we put up the piece of sheet metal with holes drilled for the bolts to slide through. Then another nut to hold the sheet metal to the studs.
The only problem we had was that the nuts behind the sheet metal keeps the sheet metal about 1/4 off of the wall of the trailer, this caused an annoying whistle when air blew behind it when driving down the road. It was louder than the radio could go when doing 70mph on the highway. To resolve the issue we simple put a piece of L channel aluminum on the trailer right in front of the signs to divert the air.
Why do people not respect us as they do other tradesmen? Because every Tom, Dick, and Harry doesn't think he can be a plumber or electrician!