for overtones, start w/ playing the whole G scale 1 octave w/out using the octave key. then move up the scales, (next would be Ab, then A, Bb, B, and so forth) until you can play the entire range of the horn w/out the octave key. if you can do this, then you will know basically how to produce an overtone. from then on, it's all a matter of how much throat variation to apply. its easier to explain in person, but maybe you'll be able to figure it out on your own. just be sure to not tighten your lips, or clamp your jaw down on that mouthpeice. maybe that helps somewhat, Joel