What can you test on the scoot with it? Many things. Only it won't test high amperage like in the starting circuit. Gotta have much bigger one for that.
Still, it's good for showing battery volts -- motor running and/or not running.
Continuity: that'd be a good test for that switch you're talking about. Continuity needs to be checked when there's no current going to/through the part in question. Otherwise you blow the meter's fuse!
A cheap little set of jumper wires with alligator clips helps many times so you can attach your leads to what you're checking. Otherwise, seems like you need three or four hands.
When you turn the dial into the different sections, you read a different line on the meter face. The lines are all marked at one end or the other as to what they're for.
Check the meter's battery by turning dial to the highest Ohm setting, then touch the two leads together. Should make the needle go all the way across.