The default Slide Layouts available in PowerPoint help you choose various placeholder arrangements for your slide content — it’s easy to create good looking slides using them. As an analogy, duplicating and editing a Slide Layout is more like using a coloring book to fill color between the lines of pre-drawn art — but creating your Slide Layout from scratch is more like starting with a blank sheet of paper and drawing your art before you start coloring between the lines. Decide which of these approaches works best for you before starting. If you prefer the latter approach, follow these steps to create a new Slide Layout.
Learn how to add a new slide layout within Slide Master view in PowerPoint 2011 for Mac.

