Just answer all of TurboTax's questions carefully and accurately without overthinking them. TurboTax will automatically prepare 2021 Form 8606 to determine the taxable amount of your Roth conversion. Line 14 of that form will carry forward to line 2 of the next Form 8606 that you next need to file when you take another traditional IRA distribution in the future.
Be sure to click the Continue button on the page that lists the Forms 1099-R that you have entered, otherwise you might not have reached all of the questions needed to obtain the information needed to complete Form 8606.
