Before setting up a Minecraft server with Fabric Mod loader, it may be a good idea to install Fabric in a MultiMc instance, download and test mods in that instance, and once you have everything set up and working, only then set up the server. You can do that here.

Create a folder in any location in your computer that will be used by the server, for example:

c:\mc-server

Go to https://fabricmc.net/use/ and select the “Server” option, then download the Windows exe installer or the Universal JAR installer and save it in the folder you created, for example:

c:\mc-server\fabric-installer-0.4.2.27.jar

As an alternative, or if you want to use the latest version of Minecraft, go to https://www.minecraft.net/en-us/download/server/ and download the Minecraft server jar file. You must save it as server.jar in the folder you created, for example:

c:\mc-server\server.jar

If you want to download the Minecraft server jar for an older version of Minecraft, open the Minecraft launcher and follow the steps outlined in the following images. Remember to save the file in the folder you created, for example:

c:\mc-server\server.jar