Wrap your thumb and forefinger tightly around the "trumpet" end. Form an air chamber with your hand, (As if you were gripping a golf ball). Make sure you have a small gap in the air chamber by slightly lifting one finger. Put the tip of the call against your lips and lightly "sip" or "kiss" into the end of it. You are actually sucking air through the call. Adjust the size of the gap in the air chamber until you get it to "yelp". Some guys use two hands to form the air chamber.