On the previous page you should see a photograph of Melbourne. Simply click that image, and the video should load in QuickTime. The video will then download. Wait till the video has downloaded and click "Play" in QuickTime.
If you don't see a photo, it is possible that your quicktime plugin is not working. If that is the case (or you just want a copy of the video to save), you can download the main version (11MB). If you are a stickler for quality, the high quality version (19MB) may be more to your liking.
If you are still having problems, it is possible that your version of QuickTime is very old. Please visit the quicktime download page to update. Alternatively, more advanced users can use the free and excellent MPlayer on Linux, Mac OS X or Windows to watch the trailer.