First time using Turbotax, so it has no records of past returns. How/where do I indicate overpayment credit from 2021 taxes that should be applied to this year's return?

To enter last year's refund you applied to this year.

Federal (Personal for Home & Business)

Deductions and Credits

Then scroll way down to Estimates and Other Taxes Paid

Other Income Taxes - Click the Start or Revisit

Next page scroll down to 2021 Refund Applied to 2022

Click Start or Update by the tax you applied

Then for state, you need to click on the state tab and go through state again for it to update.