Typically, in a lot of phones you have to search through volume settings to find out where the option is to mute your phone. Most first time BlackBerry owners go through the media and general settings first trying to find this option. Really though, the "Quiet" mode is in plain sight on the front screen of the phone. The options are preloaded sound profiles from BlackBerry. These are "Loud," "Vibrate," "Quiet," "Normal," "Phone Only," and "Off." Knowing where these are located will help you quickly mute your phone in a class or at a movie.
Scroll the trackball to the right on the homescreen of your BlackBerry. This highlights the sound control button.
Press down on the trackball to open the menu.
Scroll down and select "Quiet" with the trackball. This mutes your phone of all sound except the camera shutter.
To mute the ringer when you receive an incoming call, press the silver button at the top of the phone. It has a picture of a speaker with a line going through it.