What do you want to know? If you're thinking of doing this, go for it, you'll love it. I built my own aluminum flatbed, and put a 2007 Lance 805 on a 2017 F350 CC LB 4x4. I closed the sides in with hinged aluminum panels. The panels have cable stays, so when they're open, they make a large table surface.
Here it is, bringing it home, redneck style. Yes, those are 2" ratchet straps running under the deck. Picked a nice day with a 40 mph cross wind most of the 300 miles home.
Here's the drivers side door. There's storage, 6 gallons of water, and two 6 gallon holding tanks behind the door.
Here's the driver's side open.
Here's one of the passenger side, before the door was installed. There's a porti-potty, four MFC water cans, a water heater, and a 11lb LPG tank for the water heater.
I had this idea years ago, just didn't ever follow through until now. I found the same picture you posted, and it got me fired up to finally do it.