Typically it is located with the other AV equipment. Ours was gray with pushbuttons to select DVD, Antenna, park cable, or Satellite for each TV. Basically each source comes into the box, and you can select which source you want for each TV. That changed in our 2017 Discovery when the newer TV's allowed you to chose inputs at the TV so they started wiring the sources directly to the TV's. Can't say for sure in you unit, but a call to the technicians at Fleetwood in Decatur should get you an answer you can trust.
I have to agree, the walkthrough by most dealers is nearly a waste of time. Even if they covered everything, they are trying to do it is such a short time that it is like trying to take a drink from a fire hose.
