There is no one 'future tense' in English. There are several 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.