The Center comes with generic instructions. Actually it is fairly simple. The hard part is knowing which coax (in the Montana) does what. Once you figure out the source connections and the output connections it is easy to hook to the back of the Center. Since the Center comes with its own booster (for the ant) you need to bypass the existing booster, which also give you access to the ant Coax and the two TV coax. The Winegard website has a manual download
http://www.winegard.com/mobile/pdf/2451991.pdf (2 TV version) or
http://www.winegard.com/mobile/pdf/vs-0604.pdf Is the rear connections for the 3 TV version.
Only electrical connection you need is a 12 volt dc source, which is also on the existing booster. The wire and connector for the Center is included.
The Center operates on 110 volts with the supplied cord.
Then the tricky part is the typical input output to the DVD, VHS, Satellite receiver, surround sound and TV's. But the Center makes that almost a simple matter of hooking each component to corresponding jack on the back of the center.
Sorry but I don't do house calls especially clear across country in VA. I would be willing to bet there is a MOC member much closer that might be able to give you a hand if you run into trouble. You can always PM me also. Check out the manual and see if it looks like you CanDo the job?