"if" always introduces a conditional sentence. However, some people say that the zero conditional is not a true conditional. There are also mixed conditionals.
In my view, the best way to study conditionals is to study the precise situations when you need to use them, in context, and then learn the form. There are lots of resources in course books and online.
Learn the zero, first, second, and third conditionals together. (Mixed conditionals can be left for when you are advanced.)