how do I re-import my 2023 taxes into my 2024 file?

[xmasbaby0]

What do you mean by "re-import"?   You have to do the transfer of  the 2023 tax file in to 2024 at the very beginning before you enter any 2024 data at all.  You cannot do that again after you already started working on 2024.  If you did not transfer the 2023 tax file at the beginning, you will need to start over.

How to transfer last year’s return? 

https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/transfer-last-y...

[DoninGA]

To do that you will need to clear your tax return and start over.

If you have not paid for the online edition you are using, have not filed your tax return or registered the Free edition, then you can clear your return and start over. Click on Tax Tools on the left side of the program screen while working on the 2024 online tax return. Click on Clear & Start Over.