I've had one walk through in the Material Room on Saturday, and now looking at those screenshots, I actually understand what is going on :) I see that when I do starting working in that room, I'll have to reposition the windows and work from left to right instead of right to left as in the screenshots. To me it makes more sense to see how something starts on the left... ie: the black texture, and how the added nodes and adjustments make changes and ultimately progress to a final result on the right instead of vice versa. I think that is part of the problem. I've been trying to read them from the left when in fact the way they are layed out in most screenshots is to be read from the right.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi