Scene components as such have no visual representation in a multi-touch scenario. Their function is to structure multi-touch projects into different scenes, of which only one can be shown at a time. Scene components are top-level parents that contain child components such as layer components et al.
For more information on the relationship between Scene components, Layer components and other components, see the Understanding the Scene Manager section.
Creating a Scene Component
Simply drag and drop the Scene component from the Library into the Stage. Also, a corresponding entry will be created in the Scene Manager. By default, every project has a Scene component in the Scene Manager. It's not possible to have a working multi-touch scenario without a Scene component.
Using a Scene Component
A Scene component can be thought of in the same way as a movie scene: it is a particular setting with its particular content. In one scene, you focus on a certain kind of content treating for instance a specific product or a game to play.
If you want to proceed to other content, the best way is switching to another scene in which you have organized that content. To switch between scenes you just need to make the new scene visible, which automatically hides the original scene. This way you don't need to care about handling the visibility of dozens of individual components.