Story telling is a very important tool writers use, and one of the oldest. Let's look at it a bit more abstractly. First, narration is talking about something that occurs in time . The simplest form of narration is telling something in the order in which the events occurred, or chronological order . The secret here, of course, is knowing the pace of the storytelling, so that the climax comes at just that point where it has the most effect.
Narrations can be short, as with anecdotes, or much longer accounts.
Sometimes a writer will choose to put a whole section of an essay or a book in narrative form. Indeed, some entire books are narrative accounts. There are lots of variations from the straightforward chronological order. If somewhere in the story the narrator desires to reach back and tell an earlier part of the story, that's called a flashback . You can also have flash forwards , which might tease the reader about what's coming.