An outline of your narrative should consider your audience and the order in which they should receive the information. Sometimes it's beneficial to include an introductory paragraph, but many authors begin a narrative by just jumping into the story (in medias res: in the middle) to make the story more effective.
Narratives typically tell the story of one event—constrained within a specific time period—in order to make a point or observation about a larger issue.
A typical narrative prompt might ask you to think about a moment when you had to make a quick decision, describe the moments leading up to it, the factors you considered in making the decision, and the consequences resulting from your decision.