Leave a comment and the past the link into the comment.

Like this:
https://steemit.com/twentyfourhourshortstory/@mctiller/writers-win-5-steem-in-the-24-hour-short-story-contest-topic-2-for-january-26

all I did was copy the link from my browser and then pasted it above. Put your story with the link I just pasted.