The editor styling is to allow you to be able to create your own custom css styling for users to be able to utilize in your editor instance. If you create your own css file and select that, you will be able to include the different classes that the user can then use. The available styles listed will need to be selected to show up in the editor. Click on them and then use control/command (depending on your operating system) and click to select additional styles you want in your editor.