A slide layout in PowerPoint is like a blueprint for a house; it establishes the various types of "rooms" that appear on your slide. Just as certain types of rooms contain certain types of furniture, slides can contain different types of objects. A title and content slide will hold a title and bullet list, while a picture with caption layout will hold an image and some text describing it. The placeholders in a layout automate tasks involved with creating and formatting contents specific to each type placeholder.
In PowerPoint 2003 and earlier versions, there were slide layouts with bullet point content and others with graphic and multimedia content. In PowerPoint 2007, layouts with content now include both bullet point and graphic/multimedia content tools on one slide. You have to pick one or the other, though: When you use either of these tools to add content to these placeholders, the other tool disappears.
Click and drag to draw the placeholder where you want it to appear on the slide.
If necessary, click on the placeholder to select it and drag it to a new position on the slide.
Click the Close Master View button to close the Slide Master. The additional placeholder will appear on every slide of that type in the presentation.