Fortunately, the TV's in the bunks are actually made for 12v. Had you purchased them new, I suspect you would have received both cables. You need some quick splice connectors, 50 foot of 16 gauge/2 wire cable, zip ties, cable raceway, 2 -12 volt outlets and the skyworth 12v replacement power cord.
I used home depot for the cable, connectors and cord raceway. Purchased the Skyworth adapter and 12v lighter outlet from 12volt-travel.com. (you need the model number from one of the TV's.
Install involves removing the bottom bunk top. Pull of the bottom bunk matress and you find a sheet of plywood held into the bunk with screws. Remove all the screws and the plywood bunk platform. You will find the main 12 volt power feed to the bunk led lights sitting at the bottom to the left. It is tucked away so look for the small wires from the bottom bunk led light.
Rather than type out a long installation manual, I will shoot some photos of my install on Wednesday. In the meantime, here are some links for parts:
12v Lighter Outlet
12 Volt Clip-On Battery Platinum Series Cigarette Lighter Adapter RPPSAPS
12v DC Power Cord for TV
12 Volt Clip-On Battery Platinum Series Cigarette Lighter Adapter RPPSAPS
Cord Raceway
Wiremold/Legrand 5 ft. Cord Management Channel-C1 at The Home Depot