Hola,
Usually when we find community created guides, we try to list them on the wiki to make it easier for other users to find them as well. See:
In this case, I have not seen any community guides for installing AtoM using Ubuntu 20.04.
Please note: AtoM 2.6 and earlier has NOT been tested with Ubuntu 20.04 and its default PHP version, PHP 7.4. If you try to install AtoM 2.6 or earlier using these, you will probably encounter errors.
Atom 2.7 will use Ubuntu 20.04 and PHP 7.4, but it is still in development and is not currently suitable for use in a production environment. In the upcoming version, we have replaced the web installer with a fully command-line based installation process, to avoid timeout issues. You can see the new installation documentation for this version here:
Good luck in your search,