2003 Chevrolet Silverado Oil pump

It's driven by the crankshaft snout. Gotta rotate the engine to drive the oil pump. I prefer to bypass the starter relay to spin the engine with no spark or fuel for a newly-rebuilt engine. Of course the bearings and cylinder walls will have been coated with engine assembly lube, so even if you just start the engine, the vital parts will be lubricated. If you're just replacing the oil pump, the passages are already full of oil. Just start the engine like normal.