Use music theory to improvise at the piano. The exercises are not meant to teach theory, but to draw a students attention to concepts that they will need later, when they study 4 part writing.
Piano teachers can even teach these exercises by rote, and later point out theory, bringing in the written music.
Students doing self-study will need a reliable reference book to work with, while doing these exercises.
The exercise are written for Intermediate Level Piano students, and need to be played, studied and then tried out in different keys.