To use your keyboard as a guitar, turn it around so that the W looks like an M and the ESC button location is on the lower right. Now pick it up, under board (put your hands under it). Your left hand should be placed on 1 2 3 on the numpad. Your right hand should be OVER the board to reach space bar.
How to play:
When the number comes, press the number and space bar at the same time. The more combo the more score you get.