The e-learning libraries from PTC are a great way to start if you have the time to go through them all. You can access them at your convenience. It is well worth the cost.
Yes, I agree with that, the e-learning libraries are good. But, if you want to go the next level, I recommend books of mine. And in addition, free use of the real tools and machines for simulation and lot of more professional way to work.
The following links could be helpful for you to learn NC machining