Hello and welcome to Just Answer!
The oil pump is located in the front of the engine and is mounted to the crankshaft nose.
To replace the pump you need to remove the oil pan, pick up tube, timing chain cover, timing chain tensioners and the oil pump.
I hope this helps, let me know!
Thays what I thought It starts out with good oil presuure and then drops to nothing wondering if the screen is plugging up
Usually if the screen is plugging you will have low oil pressure on a cold engine because cold oil won't be as easy to get through the screen. When the engine warms up the oil is able to suck through the screen easier. It is still a possibility, but it sounds like you either have a bad pump or excessive bearing clearance.