BMW 318 1.8 alarm

Hello everyone,

I would like to know if someone has a track about the original BMW 318 1.8 alarm

when the car is closed with the key, it is activated but when entering inside it
they begin to turn on the flashing lights of the alarm system, but it does not emit any sound,
I do not know if it has a cirena or the same horn acts as a sound alarm. I also do not know where these devices are located.
I would appreciate a lot, someone can help me since the car sleeps in the street, and I sleep with a single eye all night. Thank you.