If we are going to try to describe the actual procedure, then:

Don't do something like turn the headlights on, or turn the key to "on" with the meter connected as an ammeter -you will blow the fuse in the meter!

As Padgett pointed out, there will be, usually, two scales/ranges on the meter, one for about 10 amps and one for under .2 amp (200 millliamps). If you connect the meter on the lower scale and see NO reading - you have blown the damn fuse in the meter! So buy extra fuses for the meter when you buy it.

Also, there may be TWO fuses in the meter -one for the 10 amp scale and one for the .2 amp scale.


(Oh, and I'm an ELECTRONICS genius, not electrical. )
(Well, its more like savant syndrome than Genius. It's all really complicated - not Avril Lavine Complicated, just complicated.)