By now, your story should be published.

Click on the search icon at the top-left corner of the site to search for your book's title.

Right-click on the book's title and copy link address (or tap and hold on the title if you're on mobile, the "copy link address" option will pop up)
See screenshot below:


Alternatively, you can get your story's link by clicking on the title after searching, then copying the link on the address bar

See screenshot below: