When playing C1, press the low C key with the middle of your left thumb so that the tip of your thumb is arched upwards, ready to reach other keys. Playing between C1 and D1, simply slide the thumb on those keys, keeping it in contact with the instrument. To help the low notes respond, pronounce the “O” vowel, roll out your bottom lip a bit, and drop your jaw. Keep the tongue gentle as you let the air energize the initiation of the tone. If the instrument does not respond easily, it could have leaking pads or your reed might be too open. If that is the case, close the aperture a bit by pinching the first (top) wire top to bottom.