be~ing, be going to / will

If something has already arranged or decided to do,
be~ing, be going to do.

What are you doing Saturday night?(What are you going to do Saturday night?)
I'm going to the theater.

What time is Lush arriving tomorrow?
At 11:00. Nick is meeting him at the airport.



 You can use a simple present when you talk about schedules, programs, etc.
(for public transportation, movies)

Lush's flight leaves at 11:30, so he needs to the airport by 9:00.
What time does the movie begin?
Tomorrow is Saturday.



we use I'll when we decide to do sth at the time of speaking
or predict a future happening.

I left the door open. I'll go and shut it.
Did you meet Laws? / Oh no, I forgot. I'll call him now.
The bag looks heavy. I'll help you with it.
Laws won't pass the exam. He hasn't studied hard enough.
Where will you be this time next year? I'll be in France.