Download the FBX to GLTF tool here:
Navigate to your .fbx file in windows explorer, and paste the converter tool next to it.
right mouse click in the blank space (not on the file) to open up the drop down menu, and select
Open PowerShell window here
.\FBX2glTF-windows-x64.exe followed by the name of your model. Wrap the name in quotation marks if it contains spaces.
If it successfully exported, you should see the following result in PowerShell
Then you can zip the output folder up and upload the result to Plattar