Yes, you must use schedule C to report your income and expenses. You also have to pay self employment taxes. And if you make a good amount of money, you should pay quarterly taxes on estimated income. TT does all the calculations. So that should not be a problem. Refer to below link for all the details.
Refer to
https://www.irs.gov/businesses/small-businesses-self-employed/self-employed-individuals-tax-center
