There are several ways that you can control the appearance of the ribbon.
The ribbon can be minimized so that you only see that tab names and not the command groups and buttons. To always keep the ribbon minimized, right-click on a blank area of the ribbon, then select Collapse the Ribbon from the menu. (To revert this setting, click on one of the tabs, then right-click on a blank area of the ribbon and deselect Collapse the Ribbon from the menu.) You can also double-click on an active tab name to toggle this setting.