Petcock and pipe for CB77

[evandomme]

Hello,

I bought a honda cb77 tank to put on another bike.
I want to know how to put the fuel lines on the petcock.
One at the top is used to retrieve the hose coming from the other side of the tank.
One of the two pipe pointing down to the carburetor.
What is the second pipe pointing down?

Thank you very much for your help

[Atlas]

you have one hose to each carb