How do i change my files back from pdf?

I just downloaded the new version of libreoffice. Now my files will not open. Writer, I just updated yo the 7.0.6 version of libre now my files

How to ask a question/getting started

If you open Writer, then click File > Open, navigate to and select an existing file, then click OK, does it open? If it does, then please describe the problem as well as adding OS and version, & LibreOffice version. Cheers, Al

BTW odt is correct format for Writer files