Form 8606 not populating

Form 8606 is for nondeductible contributions. Did you make your contribution nondeductible?

1. In the Deductions & Credits section of your Federal return, scroll down to Retirement and Investments. Click Show More and click Revisit/Start next to Traditional and Roth IRA Contributions.
2. If you converted to a Roth IRA, your original contribution was to a Traditional IRA. You then should have received a 1099-R for the conversion from a traditional IRA to a Roth IRA if you both made the contribution and the conversion in 2021. For a proper back-door Roth, you will want to select Traditional IRA.
3. Select No to Is This a Repayment of a Retirement Distribution?
4. Enter your contribution amount, making sure to put it in the appropriate box if you contributed in 2022.
5. Select No to Did you change your mind? For more details on the differences between conversions and re-characterizations, you can click on the TurboTax help article.
6. On the Choose Not to Deduct IRA Contributions screen, select Yes, make part of my IRA contribution nondeductible.

Once the contribution is marked nondeductible, Form 8606 should populate.

The actual contribution was made years ago, this was just a conversion in the current year for future tax purposes.   When I put numbers into the deductions and credits - TT says excess as it believes I made the contribution of, for example, $50,000 this year.   

Sorry about the misunderstanding. Was the conversion in the year 2021 or did you not do it until 2022? If you did it in 2021, you should have received a 1099-R. That is where you will report the conversion, not in the Roth IRA contributions that I was referencing in my last post. To enter the 1099-R for your conversion from a traditional IRA to a Roth IRA:

1. Search for 1099-R and select the Jump to link in the search results.
2. Continue through the screens to import or enter your 1099-R form.
3. The IRA/SEP/SIMPLE box is checked.
4. When asked What did you do with the money? select I did a combination of rolling over, converting, or cashing out the money. Enter the money converted to a Roth and Continue.
5. After a few more screens, it will ask Any Nondeductible Contributions to Your IRA? If you had a basis in your traditional IRA account, you may enter it here as well as the starting and ending values of the IRA so TurboTax can determine the taxable amount of the conversion. 

If you had a basis in your traditional IRA, you should see Part I of the 8606 filled and the taxable and nontaxable portions of your conversion in Part II. If the entire amount was taxable, Part I would be blank and the entire taxable distribution would appear in Part II.