How do you prime a oil pump for a 1999 F150 4.2 V6 engine?

Assuming the new pump was primed before it was installed, I would disable the ignition, the fuel injectors and the fuel pump, remove all 6 spark plugs, then with the proper amount of engine oil in the engine, crank the engine over with the starter for 10 seconds, then give the starter time to cool (a few minutes), then crank the engine over again for 10 more seconds, again letting the starter cool. Do this until the oil pressure gauge shows oil pressure. Now you have primed the pump and the engine. Reassemble and start it up.