US Soccer has some great instructional videos to teach new referees the Laws of the Game (LOTG). I found these helpful because the details of the LOTG are a lot more involved than the typical player would expect.
With study of the videos, and not much more than that, a referee can pass the certification exam.
When you are certified- US Soccer sends you your badge, your certification card and the Laws of the Game book. This book (perhaps better described as a booklet) is a nice summary of the rules and fits nicely into the smallest pocket of your backpack. Probably 20 pages.
For a year I used this as my go-to study guide. A few months ago I heard that IFAB had agreed on some law changes that would take effect in June, 2016. I went to their website and downloaded the 2016/2017 LOTG.
200+ pages later I had the real rules.
The summary book that US Soccer provides is great for governing a U9 level game. You read it an have some questions but feel reasonably confident to grab a whistle and blow it at the right time
But proper governance requires understanding all 200 pages. The scary part is that I was a year into my career as an official BEFORE I HAD EVEN HEARD OF IFAB THE BROADER RULE SET.
Part of this could have been a gap in my education. Perhaps US Soccer doesn’t want to overwhelm new referees with the tome which is the LOTG (probably the reason and a good idea nonetheless). But is tough to establish legitimacy on the field when a coach is barking at you about some minute detail and you are referring to a 20 page summary of the laws. And if I were to be an officious official- I really need to know what I am talking about.
Now I want to complain about how different leagues are adopting the new LOTG at different times, but forgive me…I have 200 pages of studying to do.