Every document you will encounter in the editor belongs to some entity.
You can see the list of the entity's documents by clicking its name in the left menu:
To create a new document, click Create in the list.
To edit a document, double-click it in the entity's document list, or select it from the list and click Edit:
To delete one or more documents, select them from the list and click Delete. You can also click Delete while you're editing a document to delete it.
Setting up data structure (Charon)
Editing documents (Charon)
Creating game data file (Charon)
Accessing game data (C#) (Charon)
Launching data editor (Charon)