In the Data Model & Catalogspage you can create relationships between Classes.
When you access the Data Model & Catalogs page, you will be asked to select a model type to edit.
Create relationships between Classes
Instead of adding an Attribute to a Class you can add a Class.
Follow these simple steps:
Select a Classelement from the canvas.
Add an Attribute element from the left side of the screen and drop it onto your Class.
Under Type, you can select from the dropdown list all the Classes available in your database.
Give it a name and press the Save button in the window.
Press the Save button in the page, found in the upper-right side of the screen.