When starting a new story you are given options to choose from a number of story templates (including a blank one), or to start by importing content from the web or a PDF file.
You'll see these options after clicking the 'New story' button on the dashboard. Choose the 'Import' option:
The next screen enables you to choose to import from a web address or PDF, as well the choice to apply AI Auto Layout to the content after it is imported:
If you choose to not apply Auto Layout, the content from your source will be imported with very minimal styling, ready for you to edit and style as you wish.
If you do choose the Auto Layout option, then on import your content will be read and processed by the system to determine logical blocks of content, and then styled and divided into appropriate headings and story sections which you can then continue to adapt and style.
Read more about Auto Layout here.