On the chapter page, on the same bar with the Like button and the Comment button, there are three dots. Click those and choose ‘Edit Chapter’. On the next page on the right side it says, ‘Link chapter’ and ‘Delete Chapter’. To delete a story, click the downward arrow next to notifications in the right upper corner and choose ‘My stories’. Then click the three dots to the right of the story entry and choose ‘Edit Story’. On that page, there is a ‘Delete Story’ button on the right panel.