Much or Many is a confusing choice that ESL learners have to make when they are speaking or writing in English. It's really not that difficult once you get the hang of it. The key is to focus on your noun - is it an uncountable (non-count) or countable (noun)?
Once you determine which one your noun is, you can choose.
Much is for uncountable nouns (such as water, honey, and time), while many is for countable nouns (such as kangaroos, phones, and towels). Also, we use much in negative sentences usually, but not often in positive sentences. For example, I don't have much experience. Many is used often with both negative and positive sentences.
You should watch the video for a more detailed explanation.