Mechanical Gauge installation...Oil, Coolant, Amps...

[Mark B]

Hey guys,
I just bought a cheap set of gauges to put into my beater. I didnt realize when I bought them that they were mechanical. I still want to install them, but I am now unsure how. The AMP meter and the Coolant temp gauge seem easy enough, but how do I install the oil pressure one? Its very vage in the instructions.

Thankx in advance,