That’s really a big gap and I completely missed it.
There is a part about navigating namespaces I didn’t link to, but it’s REPL based and doesn’t explain the convention with source files. I can see now how this could be a difficult thing to grasp. Even more so if namespaces are completely new to you.
I missed the gap because I was focused more on the fact that sooner or later you get to a part that’s not beginner / newcomer friendly. I’m sure we’ve all been there. That’s the nature of learning. I believe that a learner is better off if they’re not constantly looking for the hand of an elder to guide them over a problem. I also believe that by constantly offering a hand elder can hinder the learning. In programming we have yet another problem - the guiding part is often done by showing code that needs to be written to accomplish a task, when it’d be much better (and significantly harder) to show the thinking that went into solving the problem, because the code is really just the consequence of thinking. Code is the biggest distraction in programming.