1. Select the menu that you want to edit
2. Click the Manage Menu button in the menu's lower settings panel or control box.
3. Click Add Data Field in the top right of the Manage Menu item window.
4. Select a field type and title an click OK.
5. You can now set what each item will display in the new field. For the field to appear in the item template you will need to assign it to a style component.