Use the mouse curser to aim your cannon at the ball of your choice. Press space key to shoot a cannon ball with the objective of hitting and popping one of the balls. The goal is to have the highest score before one of the balls hits either the cannon or ground. If your score is high enough it will be put in the High Score data block for other scratchers like you to try to beat. Good luck!
@bmwfordman https://wiki.scratch.mit.edu/wiki for help with cloud variables