""1. Get a multimteter ""
Harbor Freight is your friend. They have a multimeter that goes anywhere from $0.0 to $10.00 [same meter]
Harbor Freight has a full page add in such magazines as Pop Sci, Pop Mech, NRA magazine etc etc etc
Trying to troubleshoot electrical problems w/o a multimeter is like trying to fake a screwdriver out of a coin gripped by a wrench
Still don't know about auto electricity?
YouTube is your friend also
Type in battery, alternator, multimeter
There are all sorts of videos of varying quality