Follow these simple steps to start using Flatpak
Flatpak is available in the default repositories of all currently maintained openSUSE Leap and openSUSE Tumbleweed versions.
If you prefer a graphical installation, you can install Flatpak using a "1-click installer" from software.opensuse.org. If your distribution version is not shown by default, click Show flatpak for other distributions first and then select from the list.
Alternatively, install Flatpak from the command line using Zypper:
$ sudo zypper install flatpak
Flathub is the best place to get Flatpak apps. To enable it, run:
$ flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
To complete setup, restart your system. Now all you have to do is install some apps!