How do I close a Project (e.g. the Tutorial)?
File > Close Project (Shift-Cmd-W) will save and close the focussed project, leaving Scrivener still running. Clicking the red (leftmost, if you’re using the grey theme) X stoplight button in the upper left of the main project window will do the same thing. If you quit the entire app while projects are open, they’ll save and close as normal and then will automatically reopen on the next launch if you’ve left “Reopen projects that were open on quit” enabled in the Preferences.
Thank you MimeticMouton. I didn’t see it when I was searching the File menu. But once you said it, I saw it!