I am still learning as well, we have the Winegard Air 360 antenna that was already mounted. In order to finish the system, we will need a Gateway (
https://winegard.com/products/cellular/4g-lte-hotspots/gateway/gateway). The switch on the wall is part of the pre-wire system. You should have wire loom already connected to the dome antenna somewhere inside your coach. I would like to be able to tell you where it is, but I have been unable to find mine.
I think my plan is to go another route from Mobilemusthaves.com. It will be a little more expensive, but the reviews are much better than the Winegard system