You should have gotten a 1099R for it. Just enter the 1099R into your return. You will owe tax on it. Your business is not part of this. It doesn't go on your schedule C.
The easiest way to get to the 1099-R entry screen is to simply search for 1099-R (upper- or lower-case, with or without the dash) in your TurboTax program and then click the "Jump to" link in the search results.
Enter a 1099R under
Federal Taxes on the left side
Wages & Income at the top
Then scroll way down to Retirement Plans and Social Security,
Then IRA, 401(k), Pension Plans (1099R) - click Start or Revisit
If you are filing a Joint return be sure to pick which person it is for.
