Very easy to use! 1. Stick the alarm to the door window with double sided tape on the back; 2, Turn the front button on the button to ON and the alarm will enter the security state. Once it senses vibrations such as window glass or door, it will sound a loud 100 dB alarm sound. After 30 seconds, the alarm will automatically shut off and will ring again when it detects an intruder. Press the button to turn off the alarm at any time.