2001 Ford Mustang 3.8 liter

I have replaced the oil pump but still not getting oil from the pump into the engine. Getting oil from the pan into the pump. But it is not circulating through the engine.
The oil pump kit I have came with a spring, small slide piston and a cap. But they do not get installed where the pump is located. Oh, just a note the drive shafts for the pump is in working order. I have read on-line those parts go behind the timing chain cover.
Can’t find a Haynes Book that covers the 3.8 liter. Any suggestions what I can try before I have to take off most of the front engine. And is that spring assembly even located there.
Any help would go a long way. Web pages, diagrams and things to try first. Kinda at a loss on this.