These guides are the working method behind the site. They assume you are researching family history, and they send you to the offices and websites that actually hold the records. Start with the beginner guide if you do not yet know the town. If you already have a comune, go to the Antenati walkthrough or the page for the record type you need.
None of these pages orders a certificate for you. When a register is missing online, the letter templates show how to ask the comune or the parish for a genealogical copy, and how to record the answer.
How to find Italian ancestors in a sensible order: collect home-country clues, identify the comune, search Antenati and FamilySearch, then write for what is missing.