Flatpak - noobient/noobuntu GitHub Wiki
Flatpak apps are available from Flatpak repositories. You can add repos in the following format, using Flathub as an example:
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo --user
Once you found an app, installing it is just as easy:
flatpak install flathub org.telegram.desktop --user
Then you can start it as usually, from the GNOME Applications menu.
Highlighted apps: