You have to transfer 2023 before you start 2024. And I don't think you can transfer using the Free Edition. So you might have to upgrade. Or are you using the Desktop program? Where do you have your 2023 return? If you used the Desktop program you need to have the file ending in .tax2023 on your computer.
How to Transfer into the Online version
https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/transfer-last-y...
You can try to transfer it but doing this will also clear out all your current entries. If you haven't filed, registered or paid you can try to clear and start over
https://ttlc.intuit.com/turbotax-support/en-us/help-article/change-service-level/clear-start-turbota...
