Click the green flag to start. Use your mouse to reveal bones. Unearth all the bones before the sun goes down. Shift and click the green flag for "Turbo Mode". -->Don't search while the words are on the screen, you won't find <---->anything. <-- You have three minutes, which doesn't include the time when there are words on the screen.
You will only be able to find one set of bones at a time, so don't give up searching. To make the game more challenging, the bones might not be very near each other, even though in real life they would be.