This is actually a pretty involved repair. You have to have the car jacked up on all 4 corners, or up on a car lift. Disconnected battery, and it is recommended you have as much gas as possible drained from the tank. Then underneath the car you will find the tank with 2 staps holding it in place. Those staps should be taken off or at least out of the way while the tank is being supported. There are vacume lines, the fuel fill and vent lines, and the wiring harness that all have to be unhooked. Once you are sure that all lines are disconnected, drop the tank and pull to the side. Wash the top of the tank off, there will be dirt and rocks on top of it, and you need to get all of these out of the way. You will see where the wiring harness goes into the fuel sending unit. Around that peice is a slide ring that has to be gently hammered counter clockwise. Once it is free from its retaining clips, the fuel sending unit will have to be wiggled out very carefully. Once out, you will see the fuel pump mounted in line on the fuel sending unit. You will have to work out how its mounted in line, and get it off and unplugged. Reinstall the new fuel pump and reverse the procedure.
Lock ring O-ring
Posibly the fuel sending unit if you were having problems with your gas gauge.