How can I upload and review .tax files prepared by someone else using TurboTax online?

I used TT for the first time this year (2023).  
Years, 2020-22 were prepared by my late father on his TT account. Before he passed, he shared the archive tax files, which were given to me in *.tax file format.
I need to review those files. Hoping someone here knows how I can do so.