A monitor serves as the background for the demo of your app. Replace the screenshot of the app with your own one. Add text in the bubbles.
The monitor frame takes some slide real estate and makes the app screen shot smaller. Therefore, use this slide composition for a general introduction of your app or website, where the screenshot serves as a generic background. For more detailed demo slides, I would get rid of the monitor all together, and zoom in to the feature you want to show.
This layout is available as either a PowerPoint or Keynote template.