tps 90 century

I'm helping a employee that I supervise who's down on his luck, divorced, and everthing else that goes along with it. He actually made his therapist cry & breakdown after telling his life story. There are many other issues other than I posted. He has a 90 century I replaced the tps for him and would like to know how to set it. I know there are three wires black, blue, grey. Somehow I need to hook a digital voltmeter up & adjust the tps to get a reading around .4 volts with the throttle closed. Can someone explain how to hook the dig voltmeter up o this tps ot the wires.