Where (or how) do I report my 2023 Federal tax overpayment on my 2024 return?

A federal tax refund from a prior tax year is not entered on the current year federal tax return.

Or, are you referring to applying your 2023 federal tax refund to the 2024 taxes owed?

To enter, change or delete a refund from the prior year applied to this years taxes (Federal, State, Local) -

Click on Federal Taxes (Personal using Home and Business)
Click on Deductions and Credits
Click on I'll choose what I work on (if shown)
Scroll down to Estimates and Other Taxes Paid
On Other Income Taxes, click on the start or update button

On the next screen select the options under 2023 Refund Applied to 2024

Or enter refund applied to this year in the Search box located in the upper right of the program screen. Click on Jump to refund applied to this year

The prior year refund amount applied is shown on Form 1040 Line 26

BUT first make sure it's not already there.  It may have transferred over from 2023.  You don't want to apply it twice.