The icons at the top let you saw, scoop, scalpel, and glue the bone. Use the Zoom tool at any time to zoom in and see more detail, or to zoom out. Activate the Inspect tool then click on a bone part to learn more about the different parts of the bone.
Your goal is to identify all the parts of the bone listed below the main image. To identify a part, activate the Select button then click on a part of the bone. To move the bone inside the viewer, de-activate the Select button, then click and drag over the bone. To change the magnification of the bone, click the Zoom In/Out buttons. If you want to play the game with different settings, return to the menu and select new options under the Choose to Display section.