Make sure the call is sitting right in your mouth. Make sure the straight edge with reeds pointing out the front of your mouth. Then make it seal to the roof of your mouth and say the letter "s". You should get a squeling sound. Then start with the yelp saying cholk or chalk, but make sure to use your jaw by dropping it just like you would when you say chalk. If that doesn't work, then make sure your reeds are tight in the call by stretching out the frame to make them tight. You might want to check that first actually.