This is how I did mine...
If you are replacing the fuel sender at the bottom of the gas tank, here's how I did mine.
First take the *new* unit and dip the brass float in a cup of water for at least 10-15 seconds to make sure there are no pinholes in it. If there are pinholes you will see bubbles, and the new unit will show Empty the next day. Then you will be doing this job again soon (ask me how I know)...
Second, I ran the car out of gas and filled it with about 2 gallons to get back home. Jacked up the front of the car to further push the remaining gas to the back of the tank. Put a drop bucket under the tank, but didn't end up needing it.
Third, disconnected the single electrical wire in middle of old sender, cut off old rubber line (buy a new one) with clamps. Then used a large pry bar with curved tip as a punch to back off the retaining ring around the old sender. Remove old sender.
Install new sender, using a new gasket. Use thick grease around the new gasket to help it stick to the bottom of the tank (ah, gravity...). Install sender so the tangs are lined up properly, not upside down, and when you whack the retaining ring around it, make sure you don't let the sender spin. The wire connector should be at 12:00 when done, on mine anyway, and the fuel line right under it.
Reattach new rubber fuel line and old electrical wire. Fill with gas and drive. HTH