I would like to add a custom Bard button that would attach a certain class to the selected element. I've read the section in the Docs on extending Bard and I understand that what I need to do is create a Scribe plugin. (Right?)

The question is, where do I put this plugin? How can I make sure that my JS will be loaded when the Bard field type is used anywhere in the cp? Is there an example somewhere on how to implement a custom button? Any help greatly appreciated.