If the kernel parts are confusing you, I highly recommend "Linux Kernel Development" by Robert Love as a high-level introduction to the kernel architecture.
If you like that, proceed to "Linux Kernel Architecture" by Wolfgang Mauerer. The first chapter contains information similar to this article, but at a much greater level of detail.
If you like that, proceed to "Linux Kernel Architecture" by Wolfgang Mauerer. The first chapter contains information similar to this article, but at a much greater level of detail.