Headings h1–h3 are used for splitting up the content file. An h1, h2 or h3 heading will dynamically split the document into new pages in the table of contents. An h4, h5 or h6 heading is used as a heading within a page.
Starting with CMSimple_XH 1.5 the plugin Pagemanager is included in the download. Pagemanager simplifies creating, renaming, moving and deleting of pages.
Even complete folders with subfolders can be moved or deleted with Pagemanager.
Thus it should be no problem to get rid of the contents of this standard download. Alternatively you could start with the present page structure, rename pages and overwrite the contents.