To Find Books, you need search only the SPU Discovery System. Searches of the SPU Discovery System can be limited to the SPU Library and to SPU Library + Summit (Summit borrowing).
They can also be unrestricted (WorldCat and InterLibrary Loan).
Try the phraseology used by Dr. Drovdahl, placing it in the Title or the Any field. You may (or may not) wish to use quotation marks (" ") to hold a phrase together as a phrase. Don't enter a term in a Subject field until you know that it is indeed an official Library of Congress Subject Heading. Then analyze your results. Watch for (and, using the Worksheet, maintain a running list of) the relevant official Library of Congress Subject Headings that your Title or Any searches turn up.
Though the official Library of Congress Subject Heading Narrative theology won't return every book on narrative theology ever written, starting with Dr. Drovdahl's phraseology turns out to be a helpful approach in this case.
Start with discipleship, by contrast,
or something like mak* disciple* (the asterisk (*) being the operator used for truncation),
and you'll soon discover that to search the Subject field (as distinguished from the Title or Any fields) effectively, you're going to have to use Library of Congress Subject Headings like Christian life, Disciplining (Christian), and Spiritual formation.
For some of Dr. Drovdahl's suggested topics, then, you may have to run