Editor
The Editor is the screen used for editing Cards. It is the main place where creation happens in Castle.
The editor contains a Belt listing all the blueprints in the card; an Inspector for editing specific blueprints, their Behaviors and Rules; a scene containing a layout of all the initial Actors, tools for editing Art and Music and Scripts; and more.
If you're new to Castle, the best way to learn how to use the editor is to follow the guide How to make your first Castle deck or Castle Academy.