I already paid my self-employment tax, how can I report it in my tax return?

If you mean you paid estimated tax payments during the year, you can enter them by following the steps below.

1. Login and click Take me to my return
2. Next, select the Federal Taxes tab and then click the Deductions & Credits tab below it  (If you have the blue button Check for more tax breaks click it, and then click Skip to see all tax breaks)
3. Scroll down to the Estimates and Other Taxes Paid section and click the blue hyperlink Show more
4. Click Start/Revisit next to Estimates, or other section as applicable.
5. Click Start next to the Federal estimated taxes for 2016. You'll be able to enter on the next screens.
   

If this isn't what you meant, please let me know more information.