The outliner allows you to modify the hierarchy of your current entity editor. Here you can create or delete entities, drag entities around, or rename them.

To create a new entity, click the + button at the top of the window.

To delete an entity and all of its children, right-click an entity and click Delete or use the Delete key.

To rename an entity, press Enter or F2.

#Working With Multiple Entity Editors

If you have multiple entity editors open. The outliner isn't able to know which hierarchy you'd like it to display. When this is the case an extra drop-down menu appears. From this menu, you can select which entity editor you'd like to link up with the outliner.