Debian Quick Setup  

Follow these simple steps to start using Flatpak
 
            1. Install Flatpak

A flatpak package is available in Debian Buster and newer. To install it, run the following as root:

      
 apt install flatpak
    
For Debian Jessie and Stretch, a flatpak package is available in the official backports repository.
 
            2. Install the Software Flatpak plugin

If you are running GNOME, it is also a good idea to install the Flatpak plugin for GNOME Software. To do this, run:

      
 apt install gnome-software-plugin-flatpak
    
             3. Add the Flathub repository

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
    
              4. Restart

To complete setup, restart your system. Now all you have to do is install some apps!