'How much' is used for uncountable nouns. 'How many' is used for countable nouns. Perhaps it would be a good idea to do some research on that topic? But the simple answer is if you can have a certain number of something - it is countable. Three cameras, four apples, five flowers. But you can't have two rices, or seven sands. So: How many apples? How much sand?

"How much" I believe is used in a singular tense, "How much money is in the vault" versus "How many" which is plural, "How many hot dogs are there". Hope that this helped!

The answer to the question "how many" is always a plain number--one, two, six, a hundred and twenty, eighty billion, or the word "none." How many eggs do I need for this recipe?" "Three." The answer to the question "how much" will always include some kind of unit of measure. "How much flour do I need for this recipe?" "500 grams."