Oh, and telling a story is so much more than relating a narrative.
How to tell a story? First I want to hear it. And if I don't want to hear it, you have to convince me that somehow, I really do. And that for some reason, I need to. And if you don't manage this somewhere very near the beginning, you will, indeed, be relating a narrative.
But you are wanting to tell a story, no? So talk, talk the way you will talk, and I will want to hear. Make me feel part of it, and I will want to hear. I can't tell you how to do this. Your voice is going to be different every time you tell a story, and your words will change. This is partly because of your stories being different, and partly because your audience is different, and mostly because in any instant you are not the same person you were an instant before.
Part of the joy of storytelling is that everything is in flux. You are free to play with the details, with words and settings and colors and reactions, you are free to modify your voice, low, loud, nasal, rough, abrupt, sighing to a tired end. You are free to do these, and in telling your story, you will do them without realizing it, merely outlining the picture you see in your head, tracing the outline and details the way you see them, clearly.
And when you are finished your story, it will be apparent that you are done. You will have made this story picture for us to look at, and it will be complete, whether the narrative has ended in entirety, or was merely a sketch you needed to put into words. It will sound finished when you are done, if you have told it well.
And if you haven't, you have been relating a narrative. Clear, concise, cohesive perhaps, but still. If you had been telling me a story I would know it.