On learning microscopy, if this isn’t too out of context, there’s a course on Udemy that you could take to get started. It’s very basic and a different technique than Dr. Elaine Ingham teaches but it should help you to be able to observe some of what’s going on with the microbes. Udemy courses seem to frequently be on sale for less than $20…

https://www.udemy.com/course/microbial-analysis-for-growers/