Hello. I am getting these errors with the demo scene within the assetlib version of the addon running on godot 3.5.
No config file found. After login, it will be created at "user://playfab_client_config.cfg".
At: res://addons/godot-playfab/PlayFabClientConfig/PlayFabClientConfigLoader.gd:57:load()
ERROR: Class 'EditorPlugin' can only be instantiated by editor.
at: instance (core/class_db.cpp:516) - Class 'EditorPlugin' can only be instantiated by editor.
ERROR: Class type: 'EditorPlugin' is not instantiable.
at: _new (modules/gdscript/gdscript.cpp:66) - Condition "!o" is true. Returned: Variant()
Also, do you have any video setting up everything from scratch?