Add title and thumbnail
Once you've recorded all the parts a final 'Preview' option will appear in the menu so you can add a title and thumbnail for your story.
How to use the navigation
Tap in the text area to add your story title. This will appear next to your video.
Tap on a thumbnail image that will appear as the title screen on your story.
You can keep loading additional thumbnail options until you find a screen grab you're happy to select.