You can start telling your story write away. Just click on the Start a Story button:
You will be taken to a new page, where you can enter a title and add a cover image and video if you would like:
You can control various aspects of appearances if you select "Design" - this will let you change the theme (you can even create your own theme), and, to some extent, the layout as well. You access these features through the "design" button:
Facebook
Instagram
Twitter
YouTube