Use of "Much", "Many" and "More" in English

Question

In the example below, I used more and much both but I can't understand the proper use-case for more, much, and many. Sometimes, it confuses that in which scenario which one is a perfect match for it. I search and see some articles about this but I am still confused.

1. Our school only has Apple computers. However, some students are more familiar with PCs.
2. Our school only has Apple computers. However, some students are much familiar with PCs.
3. Our school only has Apple computers. However, many students are familiar with PCs.

Could you please tell me how to distinguish the differences in the usage of them?

Answer 1

Here are my explanations:

1. Our school only has Apple computers. However, some students are more familiar with PCs.
   The above ^ means that some of the students use PCs more often or they like to use PCs more.

2. Our school only has Apple computers. However, some students are much familiar with PCs.
   The above isn't proper grammar IMO, "much familiar" doesn't sound correct.

3. Our school only has Apple computers. However, many students are familiar with PCs.
   The above is similar to the first sentence, just here it doesn't say "more familiar" it just says "familiar" so that just really means that "many" of the students know how to use PC, also here it's using "many students" so that could mean around 80% of the students, whereas in the first sentence it just says "some", which could mean 30% ~ 60% of the students.

I think the first sentence is the most grammatical sentence.

Answer 2

More is used when making a comparison. (The students are more familiar with PCs than with Apple computers.)

Many refers to a large number of something countable (many students).

Much refers to a large quantity of something uncountable. (The students haven't had much practice at using Apple computers.)

These are the meanings most relevant to what you are trying to say.