This is a good question, especially for new people just starting out. There are several places to get answers about SFI.
First is the SFI home page. Across the top are black tabs which each provide information to help you.
You can also type your question in the search bar at the top and you will be presented with options for an answer.
You should also be able to ask your sponsor, co-sponsor or further up-line and hopefully someone will give you a helpful answer. I find many of my questions are already answered in the forum, so you can search there or you can post a new thread to get fresh answers.
You can also ask members of the a2a and they can help you as well.
Finally, SFI offers support that is second to none. I have never been disappointed with their responses, sometimes they do take a while though.
As you can see, Support and community are just a couple more reasons that SFI is so awesome.