volt meter : tap from 12V power and car ground.
Vacuum meter : tap from 12v power, car ground.. the rubber tubing must be run from the engine bay. for carbs, somewhere near the throttle body. for EFi...go get ur car diagram to see which vacuum hose to T-joint from.
You need at least basic electrical knowledge and some hands-on skill to do this..otherwise u're just going to have a bunch of problems.