I’m very sorry!
I erased this post because it isn’t good!
I would like to structure my book by a diagram or what is it called in english?
Perhaps you think of some outline mode. In “outline mode”, you only see your headings and you can collapse/expand sub-headings to have a more synthetic view of the book (reduced to the visible headings).
If this is what you think of, the Navigator, Headings section, is your friend. You can move or rearrange (reorder) your headings at will and sub-headings (those at a deeper level than the one you move) will follow so that the logical structure remains consistent. The headings are renumbered along the move.
This assumes that headings are already styled Heading n or that the auxiliary styles have been attached to an outline level (but in this case, I don’t think you can promote or demote a full chapter because there is no implicit level <=> style as ther is with Heading n through Tools>Chapter Numbering).
So it all boils down to correctly style your book first. Once the book is “semantically styles”, any change you want to do is very easy, whether you review the global structure/outline, the contents or the formatting. Styling is really the key to taming Writer.