By clicking on this icon, the user can access the Entity and Relationship creation panel:
In this panel, you must select an Entity or Relationship type from those displayed on screen. These objects are the ones for which the user has creation permissions.
Once an object type is chosen, the different ways the user can register objects of that type appear — again based on their permissions:
To go back to a previous step in the creation process, the user can click on the previous steps shown at the top, or use the Back button at the bottom: