The difference between "how much" and "how many" depends on the type of noun being referred to:

• "How much" is used with uncountable nouns—things that cannot be counted individually and are seen as a mass or quantity. Examples: How much money, how much flour, how much sugar, how much traffic, how much time. It can also be used to ask about the price of something.
• "How many" is used with countable plural nouns—things that can be counted as individual units. Examples: How many tomatoes, how many chairs, how many people, how many books.

Summary:

• Use "how much" for uncountable nouns or price.
• Use "how many" for countable plural nouns.

This distinction helps construct correct questions about quantity or amount in English.