To navigate, use the Page Up(Down) buttons on the keyboard, while the mouse is in the frame of the 3D world, which will move you through the different viewpoints. Click on the glowing balls, within the 3D world, to advance further into the study of the human body. Look for the appearance of a finger which indicates a clickable object. Most major organs and skeletal regions are clickable and will bring up a web page with detailed illustrations and pictures of that area. Also, use the seek or target symbol to move directly to an object when it is clicked on.