Zero conditional (present simple + present simple)
We talk about what is always true or a fact.
If something is lighter than water, it floats.
If you eat too much you get fat.
First conditional (present simple + will & infinitive)
We talk about something that is possible in the future.
If the weather is cold enough, we will goto the mountains.
If he has enough money, we will buy himself a train.
Second conditional (past simple + would & infinitive)
We talk about impossible present situations.
If I had more time, I would finish my dinner.
If she were with you, she wouldn’t be alone.
We talk about imagined, unlikely or impossible events in the future
If I won a lot of money, I would buy a computer.
If Iwas the president, I would reduce taxes.