how to turn the sound on my alarm

I have an alarm on my mirage that used to beep when i locked and unlocked my car, and also when someone tried to open the doors, it would beep a warning to them. But since i brought it home from the dealers its not making any sound. Is there a switch or something that activates the alarm or turns the sound on and off? If so, can someone please tell me how to do this?? Thankyou!