The auxiliary verb going to is used in talking about intentions. (An intention is a plan for the future that you have already thought about.)
We're going to buy a new car next month.
I'm going to work in a bank when I leave school.
In the new year I'm going to stop eating so much junk.
He's not going to go to the dance. He's got too much work.
I'm not going to watch TV until my science project is finished.
Are you going to play basketball after school?
What are you going to have for lunch today?
Note: going to is often used in the past tense to talk about an unfulfilled intention. Examples: I was going to study for my grammar test, but I had no time. / He was going to call you, but he couldn't find his mobile phone. / My grandmother was going to visit us, but she fell and broke her arm.