To install Flatpak on operating systems of the Alt family, open the Terminal app and run:
su -
apt-get update
apt-get install flatpakFlathub is a great place to get Flatpak apps. To enable it on your Alt system, run:
su -
apt-get update
apt-get install flatpak-repo-flathubRestart your device to complete the Flatpak installation. Now you can install apps!