Signal pin of buzzer is connected with which Arduino uno pin
As I have read in the page you have linked, I think you should program the Arduino to provide an impulse to the signal (s) pin.

Therefore, to answer your question you can use any digital pin of the Arduino. And I guess that as long as the impulse last as long as the buzzer will produce a sound.

Here an example of code:

int buzzPin =  2;    //Connect Buzzer on Digital Pin3 
void setup()   
{         
 pinMode(buzzPin, OUTPUT);      
} 
 void loop()                      
{ 
 digitalWrite(buzzPin, HIGH); 
 delayMicroseconds(50); 
 digitalWrite(buzzPin, LOW);  
 delayMicroseconds(50);    
}