There are many buzzers on the market, but they all can be broken into 2 types, 2 wires or 3 wires.
The buzzers with 2 wires connect with the positive buzzer lead attaching to the BUZ+ pin/pad and the negative buzzer lead attaches to the BUZ- pin/pad. You will need to set the buzzer mode up in Falco modes page.
The buzzer with 3 wires set up the same, but the third wire connects to TX4 and you must jumper the TX4 solder bridge to normal. Then in Falco modes page select Pin Toggle to setup this feature to work.
The BL Heli32 software also can make your motors beep. This does not require any additional wiring. The feature is called motor beep and can be set up in the Falco Modes page as well. If you would like your motors to beep louder, then in Bl heli 32 suite increase the beacon strength.