Since the Zuks didn't ship with an oil pressure gauge, I'm going to assume you're installing an after-market set, in which case you hook them up to the sensors they came with, using the instructions that they came with.
Aftermarket gauges can be separated into two types - mechanical & electrical ...
Electrical gauges have a wire that connects the gauge sender to the gauge itself, and unless you're extremely lucky, or you know what to buy (and if you did, you wouldn't be asking this question), the factory sender will not work with the after market gauge.
Mechanical gauges use some sort of physical (ie non electrical) method to connect the gauge to the engine - an oil pressure gauge for example, will use a tube (typically 1/8") to connect the gauge to the oil galley - so there is no separate sender, just a plumbing fitting to connect the line, a temperature gauge will have a capillary line with a bulb on the end, permanently attached to the gauge (you can detach it, but, if you do that, expect to have to buy a new gauge when you're done).
On the four bangers the factory oil pressure sender is a simple switch somewhere near to the oil filter - it turns a light on/off and cannot be used with a gauge - the factory temp sender is an electrical sender usually somewhere near to the thermostat housing - if you had told us which of the four bangers you have I could be more specific, but it varies from on the intake manifold, to tucked away between the block and the firewall, completely out of sight.
