By pressing the bright blue buttons, remember which button corresponds to which sound.
After that, press one of the bright red buttons and then press the blue button, which turns on the same sound.
If you guessed right, these two buttons will have stars instead of numbers. If you make a mistake, click on the red button again and then click on the correct blue button.
Repeat these steps until all bright (active) buttons have asterisks instead of numbers. After this, the game will restart.
By moving the slider, you can change the number of active buttons.