All Ribbon tabs in PowerPoint 2010 may have any number of buttons that represent commands but they are not scattered all over the tab area. In fact, all of them are neatly arranged together in Groups. Each of these Groups has a name that describes what the commands within that Group do. For example, the Slide Show tab in the Ribbon has a group named Set Up. This contains all commands that help you set up your slide show, such as changing show settings, hiding slides, rehearsing and recording slide shows, etc. It is only sensible to imagine that you should use this Group concept while creating custom Ribbon tabs. In fact, PowerPoint will not let you add any command anywhere else other than within a custom Group.