Thanks. I am beginning to suspect that as soon as I understand the ways in which Scrivener uses Headings once and for all, this will all fall into place. Meanwhile:
Have I understood correctly that there are two ‘species’ of Headings: one as paragraph crossheads; the other as structural entities - especially relevant during the Compile and (re-)import and split round trip (our case here) because Scrivener relies on them as a ‘special’ case to recreate a Project’s (nested folder) structure?
I so, wouldn’t it be in my best interests now - before trying to Compile - to adjust this Project’s ‘build’ (and that of my other nascent Scrivener Projects in such a way that:
- I use something else for my crossheads
- I work out how to insert structural Headings?
I have conceived as this (music) Scrivener Project as consisting of roughly 20 (eventually) top level areas of interest; I have called them Topics in the (so renamed) Draft section of its Binder. If it were a non-fiction book, they might well be called ‘Chapters’, but there is no sense of sequence. They are ‘areas’.
Each (such) ‘area’/Topic are up to four levels of relevant, connected sub-areas. Non musical:
- Animals: top level Note Folder
- mammals
- marsupials
- amphibians
- backbones?
- vertebrates
- invertebrates
- cloven hoof
- etc
- Birds…
- Insects
- Reptiles etc…
These top (Animals, Birds etc) and second (Mammals, Marsupials etc) levels are all represented in Scrivener as Note Folders; not Notes.
I’m not sure where - if anywhere - what I believe I should consider what I (maybe mistakenly) call ‘Structural Headings’ fit in and/or where they intersect, whether (structural) headings can and should be applied to this part of the ‘Draft’ component of the Binder.
Under each Note folder come up to a dozen (or so) actual text Notes. I have placed Headings as crossheads to separate the paragraphs inside the notes… ‘Chord’, ‘Tetrachord’ etc.
Was that a mistake; or - at best - something that’s holding me up and confusing me?
If so, how does Scrivener best support crossheads?
Maybe my level of (mis!)understanding here speaks to a fundamentally different and much richer approach to document structure (outlines, nesting, segmenting, and generally organizing that I am aware of? If so, I want to correct that now!
So when you say:
What would those (structural?) headings look like: the names of the Folders? Actual text as ‘Heading 1’, ‘Heading 2’ etc?
As i say, I suspect that, once I can grasp and implement that, I will be almost home and try 
Where do I set these styles up?
So would I be best to create - in my case - two new Crossheads to use as paragraph ‘titles’, just avoid naming them ‘Heading’?
I’m sorry, I know I need to get this more than I do. Why am I aiming to put divisions (like ‘mammals’, ‘amphibians’) inside the text? And no, I most definitely do not want to split anything by crossheads.
I think I see that. Use a dedicated style for the title of the Note? But why not ‘Title’? Is it, perhaps, reserved for the whole Scrivener Project’s title?
I can quite easily change that; but I can’t help thinking that it would help me to know why, please 
Yes, I’d say so: just as ‘donkeys’ are in ‘cloven hoof’, which are in top level ‘Animals’ etc
Well, I definitely do want the Chord folder (which isn’t a (test) file as such, is it) and all its notes (which are text files) to be available in the Compiled doc. (Your comments about ODT also notes, thanks) so that I can replace those glyphs in it/them
So should I start to use a ‘Chapters’ naming convention for my zoo?
I have not broken down those 20 or so areas of music theory (chords, dynamics, form etc) into Parts. I could do so; but that seemed like an artificial and unnecessary extra complication.
Again, I feel sure that this is me not really appreciating how or what Scrivener is designed to do in terms of document structure. I do want to get it right, though 
Are you saying that chapters are folders and always should be named as such? And that that is the reason, actually, why I should not be giving each Note its own actual ‘Title’?
Thanks! I shall pursue it then. But may I ask for your patience and indulgence to put me straight on the questions and - obviously - misconceptions I must still have about how Scrivener works best, please?
The time you’re devoting to this is huge, I know; and am very grateful. I too have infinite time to really understand this. Thanks 