If you're checking the resistance or continuity(ohmmeter) of something, make sure the circuit doesn't have any power on it. You will blow the fuse or maybe damage the meter. If you're checking the voltage, then, set it on DCVolts, and set the range on the next setting above 14 volts, probably 20 volts on most meters. It needs to be the next setting above the voltage you are expecting to read, but not under. You can get an auto ranging meter that's easier to use. All you have to do is set it to DCVolts, ACVolts, OHM, or whatever you are checking. You don't have to set a range on the auto ranging meters. I have both kinds, but I usually use the auto ranging one, because it's just a little easier.