Open the Content Details sidebar to view the current stats of your story. Updated with every change you make, it will help you keep track of your story's progress.
Open a story in the editor and click on the words and read time totals to display the sidebar (shown below).
The following stats will then be shown:
Words
Reading time
Paragraphs
Characters
Characters excluding whitespaces
Media
Links
To hide the sidebar, just click on the x located at the upper right.