Also, I put this one in my 6.9 and I'll vouch for it. My factory wiring was already destroyed. So if you don't already have a working system and want a second tank this one is great! 62$, you can use 3/8 fuel hose with clamps on everything and get rid of those air leaking push lock things.
https://www.oreillyauto.com/detail/...-fuel-tank-selector-valve/fsv2a/2600542?pos=3
Comes with the switch and a wiring diagram. When you throw the switch it changes the tank and output on your dash. Only downside with it, is it doesn't mount in the factory location, but there are a few holes in the frame near the front tank that you can choose.
Factory wires are:
Yellow and blue are front tank sender
Blue and yellow are back tank sender
White and yellow goes to the gauge in the truck
Other two wires are the power wires from the switch they give you to the tanks you pick which one is "Main" and "Aux"
(You would ignore the red and orange factory wires and just run your own from the switch in the cab to the fuel switch)
