Pretty simple, I'm looking for anyone who can give me a detailed understanding of the graph. I can understand it for the most part but there is the finer points I would like to understand also, and if I am not understanding it correctly thats fine learning something new makes for a good day. Well to finish this off I can not find a thing for this online anywhere, probably using the wrong key words to pull it up, so any help would be greatly appreciated.

The best way to understand the graph is to accept that it means absolutely nothing and in most cases is both misleading and wrong. If you want to get an overview over classes, I recommend watching some videos from creators, like for example Anders: https://www.youtube.com/watch?v=tMRKTtna3FE