About first session

Today I learned about Zero Conditional. This is one of the English conditionals. Zero conditiinal has a clause with "if" and the main clause. For example: If you heat water to 100 degrees, (if clause) it boils. (main clause).
If "if" comes first, we have to put a comma the main clause but if main clause comes first we don't need to put a comma.
In the exercises I got 2 bad answers, the rest was right.
I need to study more the structures of English conditionals and practise the exercises.

Bye