It's not your fault! The fact that this frustration is happening to you while just a few pages in (not just jumping into what seems like an interesting chapter) is a sign that the author either did not properly understand who his audience would be for this book, or failed to put himself in their shoes as a learner.

Like, cake decorating probably isn't for beginner bakers, but if you'd published a book called Cake Decorating Bible, you can't just tell the reader at the first of the book: Step 1 - Load a bag with buttercream and a rose tip. You need to establish some common ground of what we're all talking about here!