Yes, this post is just an introduction to the very basics of DI (technically to just the very basics of one half of it, the 'stimulus-locus analysis').

Theory of Instruction goes into detail on those fundamental principles and how they apply to teaching the most basic concepts. It then shows how the basic concepts can be built up into more complex ones, and therefore how more complex ones can be analyzed to reduce them into parts for teaching.

Once you understand the details, you'll probably just say, "Oh, right, reductionism. Of course that also applies here."