Self-employment tax is in addition to ordinary income tax. When you are self-employed you pay self-employment tax for Social Security and Medicare, since that is not being withheld from your pay by an employer.
https://ttlc.intuit.com/community/self-employed/help/what-is-the-self-employment-tax/00/25922
If you live in a state with a state income tax, you might need to make estimated payments to your state.
https://turbotax.intuit.com/tax-tips/small-business-taxes/the-home-office-deduction/L1RZyYxzv
https://turbotax.intuit.com/tax-tools/calculators/self-employed/