Help a thick idiot

What setting does it go on for a volt tester to test for switchs and window parts..!!!

Help I'm simple and not done it before

20v dc

You should see 12 volts to most electrical supply

Like indy says 20v on a multi meter go to the battery put the leads on it if you got it on the the right setting it should read 12.4v or there abouts if your testing for contunuity then you want the arrow with a line symbol this checks for breaks in a wire or a switch if its working properly and so on ....

As above but if you are testing switches and for continuity when they are off the car then you need ohms.
Something like this may help.
http://www.electronicsblog.org/digital-multimeter-basics/

Yeah sorry as john said ohm test if its off the car what mutimeter are you using mine has ohm testing on it also ...

i was too scared to ask this sort of thing

lol ^
Have a look on youtube as got to be a few videos on using a multimeter for car faults & general multimeter guide on usage which would get most people started.
Do need some knowledge & common sense on these things though as easy damage the controller boards you find on a lot of switches plus more modern vehicles have soft switches sending signal to body control unit which easily damaged if start adding your own new 12v supply for testing etc.