Can you check if you have done the following?
- Enabled the plugin, and added an "Extensions to Register" Resource that defines your "level" folder. This tells Godot when to use the addon
- Added the Bezier Curves Export geometry node modifier provided, note that the modifier must be applied when exporting. This packs the data into a useable format.
- Enabled "Custom Properties" in the Blender GLTF export under Include - Data. This tells the addon what meshes to operate on.
- Enabled "Loose Points" and "Attributes" in the Blender GLTF export under Data - Mesh. This lets us export the points which contain our information from Blender.
Apologies if it wasn't clear that "Loose Points" and "Attributes" are needed for curves, I'll update the page to reflect that.