http://www.englisch-hilfen.de/en/grammar/if_type1.htm

Use

It is possible to fulfil a condition which is given in the if-clause.

Form

if clause main clause
Simple Present will-future
or
infinitive
or
Modal + infinitive

Examples

If I study, I will pass the exams.
If you see John tonight, tell him to e-mail me.
If Ben gets up early, he can catch the bus.

The if-clause can be at the beginning or at the end of the sentence.

If I study, I will pass the exams.
I will pass the exams if I study.