You must play the game and make a high score. For example, 3,500. We will wait one month and the one who has the biggest score will win the first prize. The other who has smaller high score than than the first will win the second prize. And the one who has the smallest high score will win the third prize.
Let's say:
John : 4500
Mary : 2000
George : 1500
John is the winner and gets the first prize, Mary gets the second prize and George gets the third prize. 🙂