I don't find the documentation unapproachable. Maybe you can tell us what exact questions you have, why you're using this module and what overall problem you're trying to solve. Then we can maybe help you with better advice. What "simple words" help you really depends on what problem you're trying to solve and what you know already.

Maybe you underestimate yourself. Read the documentation again. Sometimes I have to read a sentence about difficult topics 2,3 or 4 times until I understand it, every time more carefully. If I still don't get it after that, at least I know what question I would ask someone else to understand that sentence.

Maybe your problem is more fundamental. Do you know what a reference or a method is? Do you know what a polygon is? If not, these may be the topics to first get information on.

Its probably the math, module only helps you do math, doesn't teach you math :)
http://en.wikipedia.org/wiki/Plane_(mathematics)
http://en.wikipedia.org/wiki/List_of_geometry_topics#Euclidean_plane_geometry
http://en.wikipedia.org/wiki/2D_geometric_model

Understanding the jargon of a culture facilitates comprehension and communication within the context of the culture. Simple words often don't cut the mustard.