You don't know this yet!
The last grammar part of this lesson is about negations (=ontkenningen). To say something is not, you use the verb 'to do' again and put the word not after it. It is often shortened into don't or doesn't.
Don't forget: with he/she/it it becomes does. Or in this case: doesn't.
Also: The verb after doesn't does NOT get an -s, because it's already in the sentence.
"She works at a bakery" ► "She doesn't work at a bakery"