How do I enter prior year basis in form 8606, there seems to be no way to do that through the Q& A.

You have two options to enter your prior year basis from your last filed Form 8606 line 14.

In the IRA contribution interview:

1. Login to your TurboTax Account 
2. Click on "Search" on the top right and type “IRA contributions” 
3. Click on “Jump to IRA contributions"
4. Select “traditional IRA”
5. Answer “No” to “Is This a Repayment of a Retirement Distribution?”
6. Enter the amount you contributed
7. Answer “No” to the recharacterized question on the “Did You Change Your Mind?” screen
8. Answer the next questions until you get to “Any Nondeductible Contributions to Your IRA?” and select “Yes” if you had a nondeductible contribution before this tax year.
9. Enter your basis in the Traditional IRA from your last filed Form 8606 line 14

In the retirement section after you enter your Form 1099-R (make sure the the "IRA/ SEP/ SIMPLE" box is checked):

1. Login to your TurboTax Account 
2. Click on the Search box on the top and type “1099-R” 
3. Click on “Jump to 1099-R” and you should see the “Review your 1099-R info​​​​​​​” screen
4.  Click "continue" and continue through the questions.
5. Answer "yes" to "Any nondeductible Contributions to your IRA?" if you had any nondeductible contributions in prior years.
6. Answer the questions about the basis

Here is an FAQ where you can sign up for updates: Why am I unable to report my 2023 for 8606 basis?