'Much' is used when we are speaking about a singular noun. 'Many' is used when we are speaking about a plural noun. When we speak about 'many' and 'much', it's worth mentioning countable and uncountable nouns.

How do you use many and much?

Use much if the noun is non-countable (e.g., water, sand). Use many if the noun is countable (e.g., oranges, children). For example: I don't have much money.

Is it as much or as many?

Yes—we use "as many as" for countable nouns: "As many as four hundred persons attended the wedding." And we use "as much as" for uncountable nouns: "She makes as much money as he does." But English always has exceptions.