Dual tank switches and valves

[fnny6770]

I am trying to get my fuel tank situated, I have dual tanks one was already replaced but I'm looking at this valve two-way valve, does anybody have a diagram of this valve and where the lines go? It's the valve that switches from one tank to the other

 

[fnny6770]

I failed to mention this is in my 1980 GMC 1 ton dually

 

[BigT]

I will watch, as I need to fix mine up too.