The templates on which drawings are based and the symbols that are used in those drawings have a formally defined structure of layers which contain specific types of graphical information.
You can imagine each layer as being similar to the transparent gels traditionally used by animators to construct hand-drawn cartoons. For example, the background of a scene goes on one gel, major characters have a gel each, incidental elements go on another layer and the foreground scenery goes on another. Put all the gels together and you have a complete scene. It is exactly the same with layers; different elements of all the possible views of products (e.g. front graphics, rear graphics, outlines, simple text representations etc) are separated out onto individual layers and by selectively displaying these layers all of the different views can be produced.
Since drawings use many dozens of layers it would be tedious to manually turn each layer on or off to construct the desired view. Fortunately the View Menu and view buttons allow you to access several preset views by simultaneously changing the display status of many layers at a time.
You can access the settings for individual layers using the Layers Dialog.