The book's call number is like its address on the shelf.
The call number on the book will be vertical, rather than horizontal. In order to locate the book on the shelf, work your way through the lines:
Find the books in the PZ section.
Within the PZ section, find the books with 7 in the call number.
Within the PZ 7 section, find the books with .G, then 8233, etc. until you have worked your way through the call number.
If the call number is preceded by REF, the book may be on the first floor and must be used in the Library. Most other books will be on the third floor unless they are labeled as Oversized and available on the second floor.