I recently purchased a oil pressure gauge from eBay [VDO]. It has a oil line to an electrical gizmo with two connections. I am not sure how thing go together on this setup.

Can someone give me some guidance?

I am thinking of connecting it in the engine bay when I first run my rebuilt engine.

Most people remove the oil pressure switch from the top of the oil cooler mounting plate and screw a hose into it's plate and attach the pressure sender to the hose. Somebody out there probably has a picture of one installed.