Press and hold the spacebar. When the green LED will light up release the space bar and the timer starts to measure time. When you press the space bar again timer stops measure time. Use the RESET button to reset the timer. At the top you can see algorithm to mix the Rubik's Cube. Use the ON button to turn on timer. Use the OFF button to turn off timer. Use SAVE TIME button to save the time. To show or hide the saves use the 's' button. To clear save use "c" button and write number of this time. (If you want to clear all saves write "all" as answer.) I'm from Poland and my English may not be well :)