Uncountable nouns are for nouns we don’t count. These nouns might be used to describe abstract ideas , e.g., anger. They can also be used for physical objects that are too small , e.g., rice. Uncountable nouns can be used for things that don't have shape (powders, liquids, gases, etc...). To describe a small amount we use "a little" with uncountable nouns.
We can’t use a/an with uncountable nouns. To explain a quantity of an uncountable noun, use an expression or word like some, a lot of, much, or else use an exact measurement like a cup of, a bag of, a slice of e.g., a cup of coffee. In order to ask about the quantity of an uncountable noun, you say "How much?" e.g., How much water do you have?
There are some uncountable nouns that are countable in other languages but uncountable in English. Obviously they must follow the rules for uncountable nouns. Some common ones are: advice, behavior, bread, furniture, information,time,news, stuff, traffic,trouble, weather, work.
Countable nouns are nouns we can count, e.g., 1 cat, 2 dogs. They have a singular and a plural form. The singular form can use "a" or "an". If you need to ask about the quantity of a countable noun, you ask "How many?" along with the plural countable noun, e.g., How many dogs? To describe a small amount we use "a few" with countable nouns.