Add Pipewire socket permission setup for Flatpak and improve example …

…path (#1980)

wiki/Flatpak.md

@@ -120,7 +120,11 @@ Currently the game audio and microphone to and from the headset isn't routed aut
 
 3. Download the [audio-flatpak-setup.sh](../alvr/xtask/flatpak/audio-flatpak-setup.sh) script and place it into the Flatpak app data directory located at `~/.var/app/com.valvesoftware.Steam/`. Make sure it has execute permissions (e.g. `chmod +x audio-flatpak-setup.sh`).
 
-4. In the ALVR Dashboard, under All Settings (Advanced) > Connection, set the On connect script and On disconnect script to the absolute path of the script (relative to the Flatpak environment), e.g. `/var/home/$USERNAME/audio-flatpak-setup.sh`.
+5. In the ALVR Dashboard, under All Settings (Advanced) > Connection, set the On connect script and On disconnect script to the absolute path of the script (relative to the Flatpak environment), e.g. `/home/$USER/.var/app/com.valvesoftware.Steam/audio-flatpak-setup.sh`.
+
+6. In a terminal, run `flatpak override --user --filesystem=xdg-run/pipewire-0 com.valvesoftware.Steam` to allow the script to set and map your headset's microphone
+
+7. Restart both Steam and the ALVR Dashboard
 
 ### Other Applications