Where to start in the code?

Hi there,

I was looking to email objo, but I guess others might also be interested, so I am start a "discussion" about it.
I think Oxyplot is great and I'd love to contribute to it in the longer term. I downloaded the source code a few days back and started looking through it, but have a hard time finding a place to start reading code. I'm used to starting projects from scratch, or having a more "guided" type of development.

Could you please suggest good places to start in the code to get a general understanding of how OxyPlot works?