Going to is used to show a future intention. For example:
- I'm going to go on vacation next summer.
- We're going to start our own business.

Going to future sentences are made as follows:
Subject - verb "to be" - going to - infinitive verb. For example: They are going to have dinner.

Going to is used for future plans. For example:
- I'm going to see my friends this evening.
- He's going to write a book.
- What are you going to do?

Going to is also used to make a prediction based on present evidence. For example:
- He's going to fall over! (I can see he's in danger now.)
- She's going to win. (I can see she's winning now.)

Will and going to are both used for predictions and sometimes there is little difference in meaning. Compare:
- It will be sunny this afternoon. (A general prediction)
- It's going to be sunny this afternoon. (because it's getting warmer now)

Going to with the Past Simple of "to be" is often used for an intention or plan that wasn't actually done. For example:
- I was going to meet my friends but I didn't have time.
- We were going to take a vacation but it was too expensive.

Going to is often contracted to gonna in spoken English. For example:
- "I'm gonna buy a new computer."

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