There is sound, so turn on your speakers if you have them. Please wait while the video loads. It may take a few minutes. It will start playing automatically. If not, you can press the "play" button just underneat the video window. Next to that you should see the growing gray bar which indicates how much of the movie is downloaded to your computer. If the video is slow/choppy or doesn't play, try another version or size here.
Index of videos here.
If you are using a Mozilla-based browser like FireFox and the video doesn''t play, try right-clicking on this link and choosing "save target as": movie