Don't understand cams

Well, I'll start with the most elementary, not knowing if you know anything about cams. Duration is how long the valve will stay open. Lift is how far the valve comes open. This is only the beginning.
I'll just say this, more is not always better. It has to be fitting to the application. In other words, it's like lifting weights. You wouldn't ask a 15 yr old to work out with 500 lbs curling. The right amount to do the body the best, and the same is true for motors. The right one per the rest of the motor....