Won't power up, or won't display an input?
For power, the TV's need 115 AC, so you need to be plugged into shore power, running the generator, or have an inverter and have it swiutched on. If the clock on the microwave is blinking, the TV's should power up.
Once they are on, let's try to get a picture from something.
That box you describe, it does the coax input, selects which one goes where. Coax input could be cable tv, or satelite, or the crankup antenna. All can be somewhat tricky to get going.
On an 08, you'll have a dvd player, and it will probably be cabled directly to the front tv. So turn on a movie, and step through the front tv's inputs until you get it onscreen.
Check back and let us know how you did.