I've been watching more and more electronics training on Youtube. There's a lot of content. Here are some examples: Easiest way to test fuses (https://www.youtube.com/watch?v=9xuONVSs8QA) and Learn a multimeter in ten minutes (https://www.youtube.com/watch?v=g0XdCb0Iy10)
Here's some other youtube videos to see: 3 ways to test an outlet (https://www.youtube.com/watch?v=K7EeTicJeoA) and also
Double A Lithium Battery test (https://www.youtube.com/watch?v=HIcp3wgm65g&t=4s)
The videos are all from the same channel