The last paragraph of chapter 11 is supposed to describe how to bundle a database file, created during the designing state.

It does describe how to create a database file with the use of the terminal and/or the use of a tool called SQLite Database Browser.
But after this, it does not describe how to actually bundle the just created file with the application.

Is it possible for somebody to describe how to do that?

The separately created .db file can be added to the project just as any other file, using File>Add files or dropping the file into the navigator pane and checking copy items to the destination folder when the dialog opens. You then set up a class to manage the database.

Bob