ok, oil pressure, did it come with a sender unit? With either, you need to T off from the oil pressure sensor, our use an sandwich plate. With a manua gauge (No senderunit) you need to run a oil line into your car, which isn't really that great of an idea, I only would run a electric gauge. With an electric unit, you need to run a line to the sender then wire it back to the gauge, which the sender will remain in the engine bay.
With the water temp gauge, you'll need to tap the radiator with a sensor, and wire it back to the gauge, pretty easy.
Not sure on the a/f gauge, but search google or h-t. Pretty much gauge installation is the same for all cars.