The guys responsbile for doing Documents have explained things at their OWN LEVEL, and not always explained at the level of the layman beginner user who is not familiar with any of the Unreal Terms and jargon often these advanced users are familiar with because you have to understand the jargon used first in order to understand what it is they are trying to explain., that’s what causes the steep curve of learning if you don’t know the jargon language used behind all the mathematics.