You can add Routine Groups to a database either from the Physical Schemata section of the MySQL Model page or from an EER Diagram. Routines may only be added from the Physical Schemata section of the MySQL Model page.
To view an existing schema, along with its Routines and Routine Groups, select Database, Reverse Engineer... from the main menu. After the schema has been added to the current model, you can see the schema objects on the Physical Schemata panel on the MySQL Model page. The Routines and Routine Groups are listed there.
MySQL Workbench unifies both stored procedures and stored functions into one logical object called a Routine. Routine Groups are used to group routines that are related. You can decide how many Routine Groups you want to create and you can use the Routine Group Editor to assign specific routines to a group, using a drag and drop interface.
When designing an EER Diagram you can place the Routine Groups on the canvas by dragging them from the Catalog Palette. Placing individual routines on the diagram is not permitted, as it would clutter the canvas.