Not a teacher. In your example, "it" is used as empty subject. You can visit this link for reference.
Student or Learner
I have a question about the use of pronoun "it":
"It's important to understand these different strategies, for a couple of reasons. First, it will help you compare and contrast existing version control systems, in case you encounter other systems similar to Subversion. "
That 'it' seems to refer to 'to understand these different strategies'. But I thought that 'it' should only refer to real objects (a cat, a book), or abstractions (an idea, a feeling). Could it be that the passage is sloppy, because the passage is written by computer guys, who are not known for excellent writing?
In fact, "It is important to understand these different strategies" means "Understanding these different strategies is important".
So, "it" could refer to a gerund clause ( ing-clause ), but not an infinitive clause ( to-clause )?
"It" refers to the concept of understanding different strategies, not to the specific structural expression of this - at least as I see it.
A: Here is a dog. It will keep you company.
B: What will keep me company?
A: The dog will.
B: But you said "a dog", now you're saying "the dog". What is this "it" that will keep me company?
(You can see the absurdity here).