Self-Employed Filing

I have lots of questions! I have a new business but I have not yet filed for sole proprietorship. The income I expect from this business will NOT equate to a full-time job; it is very leisure. I've used TurboTax in the past for filing and used by W-2s, so I am comfortable with that process. But, 1)  how do I file with this new business? 2) Do I need to have sole proprietorship in order to file? 3) Do I need to file regardless of the amount of money I make? The forum that I will use to do business will calculate the sales tax for me, do I need to do anything else to file the taxes? Please help, thank you!