Your square is the one that is electrically charged. Move left and right with the left and right arrow keys. When your square's top color matches the bottom color of the square above you, you are 'matched,' and you can press up to switch up a row. Going off the sides of the screen or switching at the wrong time will both end the game. Keep climbing until you win!
(oh, and the three pause messages - click, win, and fail - will end when you click the screen)