Ok that's an easy one.
The "clouds" are actually part of the Shapes area. The shape has then been animated.

Go to the Insert tab and click the Shapes button. In the gallery you will see a category called Basic Shapes, locate and select the Cloud shape, move to the slide area and hold down the left mouse button and draw the cloud. Use the Drawing Tools Format tab to customise the colour etc. Move the cloud to the location on the slide you want it to start from then to animate select the cloud, go to Animations tab and click an Exit type animation such as Fly Out from the Animations gallery. Display the Animation pane to allow you to customise the direction the shape moves and the speed.

Check out my blog post which discussions animations. Let me know if you need further assistance.

http://www.thetraininglady.com/use-p...ear-disappear/