You can delete any of your stories from your account. Deleting will sync across all devices so be sure you no longer need your story before you remove it.
Step 1. You can delete your stories from the existing projects screen.
Step 2. Press and hold on the story you would like to delete. After a couple of seconds, the thumbnail will turn red and a trash can icon will appear on the story (A).
Step 3. Click on the trash can and the story will be removed.
Please Note: This deletion will be synchronised across your all devices and permanently remove the story from your account. Files are not recoverable once deleted and would need to be recreated if needed again later. You do not have a storage limit on your account so if in doubt do not delete.