Unfortunately, the RBM33G does not have a built-in beeper. But there is a GPIO where, in theory, a beeper could be connected. Here is a page that describes the GPIO circuit and the pins that could theoretically be used
https://help.mikrotik.com/docs/display/UM/RBM33G
But I don’t quite understand where it can be connected. Do I need to use only 12,13,15,16 or can I use one of the reserved ones? And how to use these reserved ones?