There is no one 'future tense' in English. There are 4 future forms. The one which is used most often in spoken English is 'going to', not 'will'.
We use 'going to' when we want to talk about a plan for the future.
- I'm going to see him later today.
- They're going to launch it next month.
- We're going to have lunch first.
- She's going to see what she can do.
- I'm not going to talk for very long.
Notice that this plan does not have to be for the near future.
- When I retire I'm going to go back to Barbados to live.
- In ten years time, I'm going to be boss of my own successful company.
We use 'going to' when we want to make a prediction based on evidence we can see now.
- Look out! That cup is going to fall off.
- Look at those black clouds. It's going to rain soon.
- These figures are really bad. We're going to make a loss.
- You look very tired. You're going to need to stop soon.
We can replace 'going to go' by 'going'.
- I'm going out later.
- She's going to the exhibition tomorrow.