Oxygen Author is highly customizable. Practically you can associate an entire class of documents (grouped logically by some common features like namespace, root element name or filename) to a bundle consisting of CSS stylesheets, validation schemas, catalog files, new files templates, transformation scenarios and even custom actions. The bundle is called document type and the association is called Document Type Association.
In this tutorial a Document Type Association will be created for a set of documents. As an example a light documentation framework (similar to DocBook) will be created, then complete customization of the Author editor will be set up.