Stories commonly have a beginning, middle and end. They connect a timeline of events that occur in the lives of the protagonist -- the main character -- and other characters that have various relationships with him. The stories take place in a setting, which is described in detail throughout the narration. Narrative answers the who, what, where, when and why of everything that occurs. In films, these become visually imparted elements. To make the leap from book or story writing to a screenplay is quite simple when someone knows general storytelling techniques.
In books and film, narration is done in several ways. The author or screenwriter commonly writes in first or third person. The author may create a fictional character or write the biography of a living or once-known individual, often in third person -- such as "Tom laughed" or "he volunteered." First person is when the writer uses "I," such as, "I ran for President" or "I picked up the laundry."
Melville's classic "Moby Dick" opens with three words: "Call me Ishmael." The author then writes from the point of view of that character, in first person. Thus, the narrator of the story is the character Ishmael. This is character narrative in a nutshell. All characters in a well-written story will have purpose, interesting qualities and participate in the overall plot. If you write your own essay about an adventure you took, using "I did this," or "I went there," you are the character of the narrative.
You may have difficulty finding narrative in such forms of writing as advertising, common journalism, poetry or speeches. But you can pick out the "storytelling" pieces if you read or listen more carefully. In some forms of poetry, writing about a tree isn't likely to be narrative, as poetry has its own stylized forms. Still, some poetry does incorporate a more narrative approach. If you want to learn to write good narrative, start by reading a few reputable novels.