The first conditional has the present simple after 'if', then the future simple in the other clause:
- if + present simple, ... will + infinitive
It's used to talk about things which might happen in the future. Of course, we can't know what will happen in the future, but this describes possible things, which could easily come true.
- If it rains, I won't go to the park.
- If I study today, I'll go to the party tonight.
- If I have enough money, I'll buy some new shoes.
- She'll be late if the train is delayed.
- She'll miss the bus if she doesn't leave soon.
- If I see her, I'll tell her.
44 EXERCISES FIRST CONDITIONAL
From Perfect English Grammar and other sources.