There is a lot of stuff in that book but 95% of it doesn't pertain to the things that sailors really need to know. Part 2, pages 12 through 17, contain all of the on-the-water things that the racers need to have a decent grasp of. That's only 5 pages.
Pages 18 through 22 (just four pages) cover how the races are conducted.
bah...the direct link won't work. You'll have to click "The Racing Rules of Sailing 2013-2016" from THIS PAGE
There are a lot of nuances that will take some time to discover and understand but you really can get started, quite comfortably, by taking the time to read through less than 10 pages in that book.