Click groups of 3 or more balls of the same color. You'll be fed as many new rows as are shown on the bottom right. To add a row more quickly, click the line at the bottom of the screen where the row is building. Clear as much of the board as you can before the last row is added for maximum points, and don't let the balls reach the top of the screen, or it's game over. Use special balls (bombs, line bonus balls) to clear more balls at once.