If a data model must be associated with the area (to get extra settings or give specific data to the user code), select it from the drop down list.
To set or change the parameters (interface) of the data model, use the button.
For example, an area might represent a sand pit. User can then create a data model named SandPit with all kind of data some other components or logics might need to process. Using the data model attachment capability, user will be able to specialize any area of his scenario.