We use enough to say that there is the correct quantity. We use not enough to say that there is a smaller quantity than we want or need - it is the opposite of too much/many. We use enough with uncountable and countable nouns.
' It costs £25. Have you got enough money?' 'Yes. I've got £30:
'Can I sit down?' 'I'm sorry. There aren't enough chairs.'
We can sometimes use too much/many and (not) enough without nouns, when it is clear what we mean.
' Here's some cake.' 'That's too much. I can't eat all that.'
' Would you like some more coffee?' 'No, thankyou. I've had enough.'
We can also use too and enough with adjectives.