The Beginner reader is not expected to have fully explored the Chronicles of Narnia storyline. A Beginner reader is assumed to have read perhaps one or two of the books (maybe even none at all). Pages marked for Beginners include some short synopses of the book plots, brief introductions to some of the key characters in the series, and overviews of several important locations where many important events happen in the series.
Much of the Chronicles of Narnia series has yet to be explored. A great majority of the character list as well as all of the chapter summaries are beyond the Beginner level.
Once the reader has completed more of the Narnia series, the next step is the Intermediate level. The Intermediate level details much more of the storyline and is suited for a reader who has nearly completed reading the series.