2020 amendment if didnt file with turbotax?

I filed with another program last year, but used turbotax for 2021. I want to file amendment for 2020 since i forgot to put in backdoor roth. Is there a way to do this using turbotax if I didnt file with turbotax last year? 

 

Also to amend back door roth for 2020, is that only a federal amend or is it both federal + state? Thank you