Beneteau 473 FUEL Tank

[JACKJ4]

I’m a new owner of a 2005 Beneteau 473. It has 2 fuel tanks, but I can’t seem to burn fuel out of the port tank. I believe I’ve identified a fuel return selector (just aft of engine above transmission) but can’t figure out how to select the tank selector to supply the engine. Beneteau manuals don’t provide any useful information. I hope someone out there can help.

Thanks!