Once a tour has loaded you navigate by clicking anywhere within the image and dragging your mouse in the direction you wish to rotate. Use the following keys to zoom:

You can navigate between tours by clicking on doors and windows that are set as hotspots. The mouse cursor will change and the name of the tour will appear in the QuickTime infobar.

If you are choosing the correct viewer for your system and connection speed yet still can't view the tours, you need to download one of the following plug-ins.