Install indicator light where it can be easily seen. By the gauge is often a good place. Use a 3/4" hole.
Install the oil and/or fuel pressure senders where they can sense the unrestricted pressure. The back of the gauge is a convenient place. A "T" fitting is provided for this.
Run a wire from the ignition switch or dash lights to one side of the indicator light. Run another wire from the other side of the light to the pressure sender. The senders are self grounding and this will complete the circuit. Whenever the ignition switch is on and the pressure is below the set point of the sender, the light will come on and warn you.
Install the temperature senders on the motor. The water temp sender must be mounted so as to sense the temp of the water coming out of the motor. If there are no open holes in the intake manifold it can be installed in the water outlet, radiator hose, or radiator. Don't install it in the water pump as this only sees cooled water from the radiator and the light will not function correctly.
Install the oil temp sender where it will measure the temp of the oil being pumped directly into the motor and after the cooler, if any. In a wet sump system without a cooler, install the sender in the oil pan.
Wire these the same as above.
Adjustable pressure senders: To adjust the pressure carefully remove the rubber plug and adjust with either a 5.5mm or 7/32" allen wrench. Turn clockwise to increase the pressure when the switch will activate. Turn counter-clockwise to decrease the pressure when the switch will activate. For reference: 1/4 turn clockwise will increase switch psi by approximately 1 pound.