Right-click the Model WORL* element provides a context menu with the single option Create Systems Group World:

Displays the Create System Group World window displayed below:

When entering the Name, the system automatically adds a / prefix so that it conforms with the internal system file naming conventions.

The System Group World elements all have a PURP attribute. It is entered into the Purpose text box as a four character keyword, and is used to identify the purpose for which that System Group World is intended to be used.