Setting up XFCE
Getting the desktop
Installing packages
Install the X server and XFCE metapackage:
sudo xbps-install xorg xfce4
Setting up a display manager
XFCE does not come with a display manager, so one must be installed explicitly; lightdm and lxdm are relatively light options that work pretty well.
Install and enable one of the two with:
sudo xbps-install <DM>
sudo touch /etc/sv/<DM/down
sudo ln -s /etc/sv/<DM> /var/service
Replace <DM> with either lightdm or lxdm, at your discretion.
After a reboot, the desktop session can be started with:
sudo sv start <DM>
On the desktop
You should've loaded into XFCE at this point. If you did, congratulations! You can go ahead and make your display manager start automatically if so:
sudo rm /var/service/<DM>/down
If you have more than one GPU and starting either display manager causes you to get stuck, see Can't start X server with multiple GPUs.
The rest of configurations here are all optional and subjective; see what you wish or don't wish to do/install.
Getting a trash bin
Unlike GNOME or KDE, the XFCE package does not install gvfs as a dependency, which is required to be able to use the trash bin. You can do this yourself with:
sudo xbps-install gvfs
This also enables the mounting of disks and SSH filesystems via the file manager.
Ricing it up
When you first come into contact with XFCE, perhaps through the Void live image, you may be a little horrified at how ancient it looks and give it a pass. However, you can achieve a lot more with just a little effort and creativity.
Here's a peek of my haphazard server install (if you're wondering, that is the Yaru theme).
Look at the settings
Note that most configuration is already available via the settings. I implore you to look through them; there's a lot available out-of-the-box. Stuff like top bar transparency and shell theming are built-in.
Installing plugins
The base xfce4 package is actually quite minimal - there's a lot more you can add to the desktop by installing individual plugins. If you're lazy and/or want everything available immediately, you can install most of them at once with:
sudo xbps-install xfce4-plugins
Below is my personal list of configured plugins which I've situated in my top bar. The name corresponds to the individual package name.
xfce4-whiskermenu-plugin: Provides a nicer combined application menu and actions menu. Looks good and resembles more what you see in other desktop environments.xfce4-fsguard-plugin: Displays how much disk space you have left.xfce4-diskperf-plugin: Displays disk activity.xfce4-netload-plugin: Displays network activity.xfce4-systemload-plugin: Displays additional system load statuses.xfce4-clipman-plugin: Clipboard manager which also includes clipboard history. Once you're used to having clipboard history, you can't really live without it.
Next steps
You'll probably want to set up audio next; Installing an audio and media server explains how to do that.