This is a mechanical timer, you must use the clockwork spring first. Please read the instructions before use so as to prevent mistakes. Note: Take the timing of 5 minutes as an example. 1, The initial state scale is 0. 2, Turn it clockwise to 55 minutes. 3, Then turn it back counter clockwise to 5 minutes, after waiting 5 minutes, the timer will sound automatically. Note: Whether you reckon the time 5 or 10 minutes, must first twist to 55 minutes, this step is spiral spring.