Linux Setup
The setup process for UE4 on Linux is pretty straight forward, and the official instructions are very well documented. Follow those steps, and return here once you're done. Below, I just outline some of the issues I encountered using UE4 on Linux post-installation and how I solved them.
For context, I am on Kubuntu 20.04. I've been able to use the editor with no issues in general, aside from one very weird lighting bug that I've yet to sort out. Here's my active question on StackOverflow
Marketplace Assets
Epic Games doesn't seem to provide any support for the UE4 Marketplace for Linux. As a result, Epic also does not support downloading and adding any assets to your project. Bummer.
I would like to note a blog post on this same issue by alexandra-zaharia, I would have very much preferred her solution but after attempting it I could not get it to work. I could install Epic Games through Lutris, but symlinking my projects (or copying them) into Wine Windows FS did not result in the Epic Games launcher detecting the projects.
What I ended up doing was using the unofficial nmrugg/UE4Launcher on GitHub. It works great, but I do miss some things like asset engine version information and browsing the marketplace.
You can install assets with it though, as long as you own them and they're linked to the Epic account you sign in with. That's all I need for now, I'm just playing with the idea of learning some C++ for UE4.
UI Scaling
Initially the UI for Unreal was very large and practically unusable. This could be due to the fact that I'm running on an integrated graphics CPU, but I'm not sure. To fix this, I just opened a project and navigated to Edit->Editor Preferences and then unchecked the Enable High DPI Support option under the General/Appearance settings menus. After restarting UE4, everything was good and UI was normal again.
Application Launchers
The shortcuts initialized by Unreal during the build process didn't work for me. I couldn't figure out why, so I just made my own. I placed these files into ~/.local/share/applications/
For the Unreal Engine Editor, the following UnrealEngine.desktop file will launch a window to open or create a UE4 project
#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Type=Application
Exec=UE4Editor
Path=/home/kapper/Code/Clones/UnrealEngine/Engine/Binaries/Linux
Name=Unreal Engine Editor
Icon=ubinary
Terminal=false
StartupWMClass=UE4Editor
MimeType=application/uproject
Comment=Open or create UE4 projects
And for the open source UE4Launcher, I created the following UnrealEngineLauncher.desktop file to run npm start in the UE4Launcher repository directory.
#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Type=Application
Exec=npm start
Path=/home/kapper/Code/Clones/UE4Launcher/
Name=Unreal Engine Launcher
Icon=ubinary
Terminal=false
StartupWMClass=UE4Editor
MimeType=application/uproject
Comment=UE4 Project and asset management