If you are interested in installing and using a Unix system based on the Linux kernel, you won't have any problem in finding all the documentation you need. In fact, there exist several excellent books that teach how to install Linux and how to run it. Furthermore, many courses are taught in many countries on the same topics.
If your problem is how to modify the Linux kernel and how to evaluate the impact of the changes you made (we call this kind of programmer's behavior kernel hacking) then you won't find as much documentation as in the previous case. In fact, you can find almost anything on the net, except that is scattered around many places and not all the documents you will find are outstanding, while many are obsolete.
So, the ambitious goal of this Kernel hacking course is to describe in a coherent way all you should know to become a reasonable kernel hacker[Written by famous author-Daniel P. Bovet and Marco Cesati, the authors of the popular O'Reilly's book "Understanding the Linux kernel"]
Have a look on this link.