No! Don't touch those screws
To bring fuel up to the filter (when fitting a new filter or run out of fuel) loosen the 'out' banjo bolt on the filter housing. And pump the primer until fuel flows from the loosened banjo. Tighten banjo. Pump a few more times until the plunger gets stiffer.
And If you have run it out of fuel, after you get it to the filter, loosen the injector pipe fittings to the top of the injectors. Crank engine with foot down until fuel starts coming out around the loosened fittings. Tighten fittings. Should start then.