the biggest purpose of mastering the overtone series is the effect it will have on your sound. Your sould will become much larger and fuller after learning to isolate the individual overtones. The only way I know to learn is kinda like learning to ride a bike, just keep at it. Isolating them is achieved through manipulation of the throat and oral cavity, NOT pressure on the reed. Finger a low Bb, and keep trying to get the different overtones. It will annoy the ..... out of everyone, but once you get it once, you'll be able to get it every time. You'll then be able to finger a note, and play bugle calls like 'revele' and 'taps'. Impress your friends! LOL