There are several DVCS around: Bazaar, Mercurial and Git. What I am going to cover here, can be accomplished by each of them. In my examples I refer to Bazaar.
You will find notes on how to install the software on the homepage of each system. It is always very easy.
To use the DVCS open a terminal on Linux and Mac OS X or the command line interpreter under Windows and change into the directory where you want to write your novel.
Mind posterity, author! Don’t you daydream that some day legions of scientists analyze your writings to find out, when you get for the first time the idea to make a tiny alien called Glimpsy the hero of your novels? Sure you do. And you can make research easier for them if you use a version control system.
WTF is a version control system? A version control system is something to keep track of changes in code.