Hi Charles,
Yes, a multimeter is a tool commonly used for checking the state of electronic circuits.
The homing endstops can be found at the ends of each axis - If you google 3D printer endstop issues there should be some good guides on how to solve some generic issues you can experience with them (not specific to the TAZ 6) such as
this article. Similarly if you don't have a multimeter or aren't familiar with it there should be endless guides online about it.
No worries, it's how you learn!
Best,
Alec