@Qaidul: there's nothing to configure. The plugin checks (after 'authenticating') if the track/album/artist of the song you're playing in MB is part of your Spotify Library or not and you can choose to change that.
@ChristopherE (and maybe Qaidul): you need to make it visible as a panel via Configure layout/Arrange panels (button right upper corner).
You will find the plugin among 'available elements' and you can drag it where you want.
Unclear, can you explain more detail.