You can find the export option on the bottom left-hand side of the interface, below the codex. If you have the codex minimised, it appears in the sidebar.

A - Toggle including everything/nothing

B - Manually select acts/chapters/scenes included

C - Toggle whether to export the scene summaries, the prose, or both

D - Enable/Disable act titles (for if you're importing into Vellum or Atticus)

E - Toggle whether to include scene subtitles

You can then choose to export your novel as a Word .docx (compatible with Google Docs, LibreOffice, etc.) or in markdown.

Yes! The formatting of the export is perfect for re-importing into Novelcrafter, and so if you're making edits you can bring the novel back as a new book in Novelcrafter.

Yes, but it won't overwrite your current versions of the same chapter. By re-importing into your novel, the 'new' chapters will append to the end of the book.

Yes! You can now export the whole novel, and select whether to include the codex, chats, and/or snippets.

Make sure that you have deselected the include act titles option (D).