alternator gauge drops and reads low when driving

I lost you on the description of the problem. The ammeter gage should drop as you drive. It shows current flow in or out of the battery (if factory wiring). After starting, there should be inflow to recharge what was used by the starter. After a short time, it should drop slowly to "0" (middle of gage). You shouldn't see the needle on the left (battery discharging) while driving steady. To verify that your ammeter works, flip the headlights on & off, and you should see the needle jump as the alternator adjusts its output (via voltage regulator).

As far as your stated limitations on electrical knowledge and tools, Harbor Freight has coupons for a free multimeter, and wikipedia and youtube have much info and tutorials on basic electricity and how to use a multimeter. The charging circuit for our cars is very simple and there is much info about common problems and fixes on this forum if you search.