First, you need to create a new process model or select an existing process model to add the business entities. If the process model is opened, you now have to open the Define Business Entity dialog from the Main tab in section Business Entities. The overlaying dialog is to choose the business entity model and with a double-click, the chosen model will show on the right side of the dialog. With OK you save and close the dialog.
In the underlying dialog, the available business entity elements are displayed. Add the elements you need for your model by double-clicking the element or with the green arrow. When added it can be configured afterward. The name can be modified as there is an option whether the entity is only to select items or to create new ones. By clicking the green 
-symbol the business entity you choose can be duplicated. Whereas the 
-symbol deletes the particular entity. Again a click on OK saves and closes the dialog.
