"Fabric is a lightweight, experimental modding toolchain for Minecraft."
Mods can be used to modify, remove or even add new content to Minecraft.
Go to fabricmc.net and download the installer.
Run the Fabric Installer jar you downloaded, select the Server tab and select the Minecraft Version you want.
NOTE You need to click show snapshots if you want it to also show fabric for minecraft snapshots.
Click install, this will download a fabric-server-launch.jar, it will also show you a button for Download server jar, press that one too.
You can now close the fabric launcher, you should have a
Upload those files to the root of your bloom server.
Go to the Startup tab of the Duck Panel and set Server Jar File to
Restart your server and let the files generate. This may take a few minutes.
You are now done, you are running a fabric server!
It's a server without mods though, so it's still purely vanilla at this point, keep reading to learn how to install mods.
Refer to this guide.