First, you need to understand the theme and mood of the poem. Then, expand on the key elements and characters to build a plot. Also, add details and descriptions to flesh out the story.
Well, adapting a poem to a short story can be done by extracting the core message or idea from the poem. Develop a beginning, middle, and end based on that. Add dialogue and scenes to make it more engaging. Just keep the original charm of the poem intact.