The first time someone builds a complex Flash project, the Timeline stretches out forever and becomes very difficult to work with. At some point in the authoring process, the designer may discover Scenes and try using those to manage the huge, unwieldy sequence of frames. However, scenes don’t make the Timeline more compact; they only break it up, the way a book is broken up into chapters. What works much better is to use movie clips for any motion or action that must be repeated or that must remain available to the user.
Movie clips are a type of symbol in Flash (the three types are graphic, button, and movie clip). They act like mini-movies inside the main movie, so they can play parallel to (or simultaneously with) ...