Advanced file features are available when the Advanced File Manager has been enabled in the Global File Upload Settings option by adding a database connection. Enable File Management must also be enabled within the Global File Upload Settings, and your editor preset must have file upload and advanced image editing enabled.
Once the above settings are configured, the advanced editor can be accessed through an HTML Editor you have inserted on a page by clicking the Insert/Edit Link, Insert/ Edit Image, or Insert Edit Flash buttons, then clicking "Browse Server" on the resulting window.