documentation improvement

[levincode]

Thank you very much, your guide helped me a lot.

I had some problems installing the flatpak, I leave you other sources that helped me:

• a more detailed guide to setup Xming
• and for those who don't know like me. add the sudo to the command:

  flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

[AbelFalcon]

Thank you very much. I will update the documentation!