How do I rename a chapter? I cannot tell which titles can be edited.

From version 1.9.22, every title you can edit in place shows a small pencil next to it, and a dotted line appears under the words when you move the mouse over them: in the chapter editor, in the outline review, in the import preview and in references. Click the title (or the pencil) and type. In the chapter editor, press Enter or click elsewhere to keep the new title. If the chapter's text repeats the old title on its first line, for example "Chapter 1: The Autumn Book Fair", that line is renamed too; the rest of the text is never touched.