Fiction writing comes in two stripes: narration and dialog. They both move the story along. Narration does it in large strokes. Dialog gets into detail at the character level.
Narration
Narration allows the writer to relay information that is important to the story in a paragraph or two. It sets the scene, describes a particular place or a specific time period.
Or perhaps it condenses the important events leading to the character’s current situation. In a novel, writers use narration to summarize earlier scenes to remind the reader how they got to that point. In each case, narration is a kind of shortcut to give the reader information or description that is important to the story.
Narration moves the story along in broad strokes. I like to use narration to summarize big blocks of time for my readers. There are few things worse than plodding through a long drawn out, play by play, detailed explanation when a quick summary will give the necessary details.
Dialog
Dialog, by its nature is personal. Conversations between characters reveal motivations, desires, and fears. At a deeper level they show us the attitudes, relationships, and tone between characters. Dialog moves the story along at the character level.
As a beginning writer you may try to capture authentic dialog. But don’t be tempted if it doesn’t move the story forward. It can, after all, be boring. Spice it up. 
Instead of saying, “How are you?” which is perfectly authentic, but also a bit mindless, let your character delve into the meat of the matter. “Gawd, where’d you get that black eye?” says so much more. It inserts conflict, shows your characters’ relationship, and makes the reader wonder how did she get that black eye?
Dialog that moves the story along has an end in sight. Everything your characters say lead you in that direction. This takes practice. Lots and lots of practice. If you naturally use a narrative style, revise to add meaningful dialog. If dialog is your thing, add dialog tags or action tags to enrich your character’s spoken words. Narration and dialog always work best when used together.
