During the design phase of your project, you will want to test the publication periodically to get an idea of how it will look to your readers. You can do this at any time by selecting one of the Run commands from the App menu. When running in test mode, you will be able to preview page transition effects, animations, sounds, videos and see how buttons and other objects behave – just as a reader would see them. This provides you with the opportunity to find mistakes and make any necessary adjustments before your publication gets to your readers.