WMS stand for Web Mapping Server, which is a technology that allows standardized communication of geodetic data between a server and a client. World Wind is a glorified WMS client, all of its data is streamed from servers available to any other WMS client.
Once you have opened the WMS Browser, you are presented with a list of images that you may view.
If you simply want view the image that you have selected, you may do so by pressing the Still Image button. In many cases, you may select a specific date or time that you wish to see before you display it.
You may have noticed a tab labeled Animation. On that page you may specify a date range, after which you should click the play button. World Wind will begin downloading all of the images within that range, and will display them one after the other. Be warned, it may take a long time to download the many images of a long animation.
The Animated Earth Manager is very similar to the WMS Browser, and as a matter of fact, the WMS Browser has access to all of the same data. The Animated Earth Manager is being phased out and will not be covered in this guide.