The timer/slider left of the playing field is counting down. Each time it resets a new row of Treasures will appear at the bottom and push the rest up. All you need to do is keep the board free of Treasures, before they reach the top. Once they do, the game is over.

To remove Treasures, click on same-colored groups of (2 or more).  The more Treasures you remove, the more you score.