Look at these sentences:
1-I like tennis but I don't like football. (don't = do not)
2-I don't live in London now.
3-I don't play the piano but I play the guitar.
4-They don't work at the weekend.
5-John doesn't live in Manchester. (doesn't = does not)
6-Angela doesn't drive to work. She goes by bus.
We use do and does to make negatives with the present simple. We use doesn't for the third person singular (she/he/it) and don't for the others.