How to report 401k after tax roth contributions?

My company offers a 401k plan which I maxed out in 2024. Then I followed Fidelity's instruction to do a Roth IRA conversion and contributed another $14K with my own after tax fund. I did not contribute to a separate traditional IRA for 2024.

 

Do I need to report this type of contribution when filling my taxes?

If so, what steps should I follow? I did not see such options when asked about traditional and Roth IRA contributions.

 

I also tried report the $14K as Roth contribution, but TurboTax indicate there would be a penalty.  

 

Appreciate any help.