Choose a book or a subject to look for in a library since using the Dewey Decimal System is the easiest way to understand it.
Verify that the book you are searching for is either nonfiction or considered literature. Literature is classified as books written by great authors and considered to be of value in the study of writing.
Work to determine the 3-digit number that classifies all nonfiction books within the Dewey Decimal System.
Determine which of the following broad categories the book or subject falls into: Generalities (000s), Philosophy and Psychology (100s), Religion (200s), Social Sciences (300s), Language (400s), Natural Sciences and Mathematics (500s), Technology/Applied Sciences (600s), Arts (700s), Literature and Rhetoric (800s) or Geography and History (900s).
Understand that every nonfiction book can be grouped into one of the broad categories and then further grouped by the more specific topic. So a book that is about physics will be in the 530s and book about chemistry will be in the 540s.
Clarify the more specific subject of your search, such as the periodic table of elements which is a more specific classification within the area of chemistry. All books dealing with this topic will be grouped together with the number 546.