Hi Jeff,
Unfortunately, I am not at all familiar with FM, just with RH.
So, RH does not have something like DITA where the topics are unnumbered, and the system, at output time, adds the numbers according to the position in TOC?
Till now I was doing that manually.
Sorry, nope – RH comes out of an online help publishing paradigm whereas FM comes from book publishing – you’re more likely to find numbering in books than online. FM does it with series labels that have building block variables that increment automatically so you can maintain numbering of things like headings, chapters, illustrations or figures (e.g. See Fig. 22 on page 426 in Chapter 14) in their captions and references to them. If you rearrange the material, an update recalcs all the series labels and references for you.