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.

Please use only h4–h6 in the content of your CMSimple pages,
because using h1–h3 will create a new page.