Testing pump pressure will tell you nothing about your fuel gauge.
Before you do anything, with your fist, hit the top of your dash above the fuel gauge with the engine running. If it the gauge starts working, you have a connection problem in the instrument cluster.
Next, find the wire that goes to the sending unit at the tank and ground it to the frame. Make sure you have the correct wire. Have someone turn the key on and watch the gauge. If the gauge responds then it's ok and the sending unit is bad. If the gauge doesn't move then it could be either the gauge or the sending unit.
Now I'm confused
It's easier to do than explain.