Personally, not learning how rules and rulebooks work early on was one of the biggest mistakes I made with this language, and I think it happened because I originally learnt from the manual alone. Writing With Inform waits for 18 whole chapters to talk about the actual mechanics of rules and rulebooks. In the first paragraph of Chapter 19, it explains that rules and rulebooks make up much of the high-level machinery of Inform (true) and in the same sentence declares that most of the time we don’t really need to know how this machinery operates (baffling and somewhat condescending)! Sure, not everyone’s going to be creating super complicated rulebooks for every aspect of their game, which is sensible. Sometimes a new adjective is all you need. But rules and rulebooks are the whole idea behind action processing, they give activities a purpose, they make source easier to manage and easier to read, they’re a principal of the language. I know enough about them now to know I still don’t use them to their full potential!
I admit that some of them can be confusing, that there’s a lot to remember about them, and that any discussion of them is likely to end up being quite dense. But I still believe that an early introduction to them would provide a more stable foundation on which someone could build a better understanding of everything they can accomplish with them.
DeusIrae mentioned the overuse of instead rules (an excellent point), which is something many have had experience with. I’m no exception. Instead rules are so easy to overuse because the naturalness of their phrasing somewhat obscures what they actually do - the role they play in action processing. I really only stopped overuseing them when I understood that role through the framework of rules. The chapter on rules honestly blew my mind the first time I read it.
So… In less pretentious language, rules: Learn to love 'em. 