First Conditional

we are talking about the future. We are thinking about a particular condition or situation in the future, and the result of this condition. There is a real possibility that this condition will happen.

Notice that we are thinking about a future condition. We use the Present Simple tense to talk about the possible future condition. We use will + base verb to talk about the possible future result. The important thing about the first conditional is that there is a real possibility that the condition will happen.

For example: 

If you study,you will pass.

If I win the lottery,I will buy a house.

If they do not come here,we'll have to go home.

If we don't hurry,we'll miss our bus.

If I have time,visit my grandmother.

If you feel sick,you go to the doctor.

I invite you to watch the video to understand more clearly.