matrix/Install-Element-Desktop.md

+_This guide has been tested with Tails OS versions **5.9**, **5.10** and **5.11**_
+
+## Persistent Storage
+If you want to keep Element Desktop persistent, we need to set up the Persisent storage accordingly: (if you want to use Element Desktop only once and lose everything after shutdown/reboot skip to section [Install](#Install)) 
+
+0. Make sure you are using an up to date Tails OS, check out https://tails.boum.org/doc/upgrade/.
+1. Create persistent storage, follow the steps on https://tails.boum.org/doc/persistent_storage/create/, skip to step 2 if you already have a persistent storage
+2. Configure persistent storage with _[Additonal software](https://tails.boum.org/doc/persistent_storage/configure/#index12h2)_ enabled and  features according to your other needs (mail, pgp, additional software) follow the steps on https://tails.boum.org/doc/persistent_storage/configure/, skip to step 3 if you already have configured your persistent storage with _additional software_ enabled.
+3. (Re)start your Tails and setup an administration password, follow section _Set up an administration password_ at https://tails.boum.org/doc/first_steps/welcome_screen/administration_password/.
+4. Choose Applications ▸ System Tools ▸ Terminal
+5. Get root privileges with executing `sudo -i` use the password set in step 3.
+6. In order to create persistent storage for [Flatpak](https://flatpak.org), a package manager we're going to use for installing Element Desktop and keeping the software, settings, keys, messages etc. persistent, execute 
+~~~
+sed -i '$ a /home/amnesia/.local/share/flatpak source=flatpak\n/home/amnesia/.var/app source=var_app' /live/persistence/TailsData_unlocked/persistence.conf
+~~~
+7. Shutdown Tails.
+
+## Install
+### Flatpak
+0. If you already have Flatpak installed with Flathub repo configured, skip to [Element Desktop](#element-desktop)
+
+1. Start your Tails with persistent storage unlocked and setup an administration password, follow section _Set up an administration password_ at https://tails.boum.org/doc/first_steps/welcome_screen/administration_password/.
+2. Choose Applications ▸ System Tools ▸ Terminal
+3. Install the package manager Flatpak with executing
+~~~
+sudo apt update && sudo apt install flatpak xdg-desktop-portal-gtk
+~~~
+4. Make the installation persistent (_Install every time_) following  step 3. at https://tails.boum.org/doc/persistent_storage/additional_software/#index4h2
+5. No we add the Flathub repository to Flatpak, executing 
+~~~
+torify flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
+~~~
+Ignore _WARNING torsocks[33952]: [syscall] Unsupported syscall number 315._
+
+### Element-Desktop
+1. Using the Terminal install element-desktop, executing `torify flatpak install flathub im.riot.Riot` and confirm with `Y`.
+2. For running element-desktop on Tails via Tor and access to audio devices, we need to set parameters running element-desktop. <details><summary>Further details</summary> Outside the unsafe browser, Tails is configured to limit network use to the Tor network only. Therefore we need to tell element-desktop using Tor's SOCKS proxy by exporting `export HTTP_PROXY=socks://127.0.0.1:9050` and `export HTTPS_PROXY=socks://127.0.0.1:9050`.</details> This can be achieved using an executable shell script, create it executing
+~~~
+echo -e '#!/bin/sh\nflatpak run im.riot.Riot --proxy-server=socks5://127.0.0.1:9050' | sudo tee -a /home/amnesia/Persistent/element-desktop.sh && chmod +x /home/amnesia/Persistent/element-desktop.sh
+~~~
+
+### Start
+1. Start Tails with persistent storage unlocked.
+2. Choose Applications ▸ System Tools ▸ Terminal
+3. Execute `Persistent/element-desktop.sh`
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