Here are the completed sentences using the affirmative form of "going to" and the provided verbs:

1. They're going to play volleyball at the beach.
2. I **am going to watch** TV at home tonight.
3. We **are going to visit** our cousins in Spain next summer.
4. She **is going to study** physics at university next year.
5. My best friend **is going to move** to the USA.
6. My brother and I **are going to do** karate this evening.
7. You **are going to tidy** your bedroom this evening!
8. My friends **are going to have** a barbecue next weekend.