"many" is for countable and "many" is for non-countable.
In general, “much” is singular, and “many” is plural. However, in context specific situations, the rules may be bent.
How many apples are there in a case? - plural
How many is too many?” – singular
How many calories are there contained in a chocolate bar?- plural
How much is this carton of eggs? – singular
How much are those boots in the window? –plural