Document additional steps for setting up AppImage installs

Author: pol-rivero

README.md

@@ -237,13 +237,17 @@ flatpak install flathub io.github.pol_rivero.github-desktop-plus
 
 </details>
 
-### AppImage (any distro)
+### AppImage (any distro, not recommended)
 
 <details>
 <summary>Click to expand</summary>
 <br>
 
-**NOTE:** I recommend using your distribution's native package manager (or Flatpak) instead of the AppImage.
+**IMPORTANT:** I strongly recommend using your distribution's native package (APT, RPM and AUR packages above) or Flatpak instead of the AppImage, as it requires some manual setup for the sign-in feature to work.  
+If you need to use the AppImage, follow these steps:
+1. (Only if downloaded without "AM"/"AppMan") Manually [create a `.desktop` entry](https://wiki.archlinux.org/title/Desktop_entries). If you used "AM"/"AppMan" to download, this step is not necessary since it creates the .desktop file for you.
+2. [Create the `application/x-github-desktop-auth` MIME type](https://wiki.archlinux.org/title/XDG_MIME_Applications#New_MIME_types).
+3. [Edit the MIME associations list](https://wiki.archlinux.org/title/XDG_MIME_Applications#mimeapps.list) to link the two.
 
 #### Using ["AM"/"AppMan"](https://github.com/ivan-hc/AM)
 

docs/known-issues.md

@@ -245,6 +245,8 @@ If you see an error that says "Not enough resources are available to process thi
 
 Related issue: [#54](https://github.com/pol-rivero/github-desktop-plus/issues/54)
 
+First of all, make sure you are not using the AppImage package, as it requires some manual setup for the sign-in feature to work. Instead, I strongly recommend using your distribution's native package manager (APT, RPM and AUR packages above) or Flatpak.
+
 After following the instructions in your web browser to authorize GitHub Desktop, the callback is not sent to the app and it remains stuck on the "Continue with browser" screen.
 
 The most likely cause is that the URI scheme used by GitHub Desktop Plus for authorization (`x-github-desktop-auth://`) is not linked to the correct program. You can verify if this is the case by fully closing GitHub Desktop Plus (`Ctrl+Q`) and running the following command in your terminal: