🚀 go-pugleaf

There may be several issues at work here. Issues to consider are:
1. How you set up autonumbering in the paragraph formats
2. How you split the files into a book
3. How you setup the numbering scheme for each file in your book

Consider this scheme for setting up autonumbering in para formats:
For parts, setup Heading1 autonumbering as <$volnum>
For Section1 setup Heading2 autonumbering as H:<$chapnum>
For Section1.1 setup autonumbering as H:<$chapnum>.<n+>
For Section1.1.1 setup autonumbering as H:<$chapnum>.<n>.<n+>

I think this scheme should work if a Part is a file, and Section1 starts a file containing the other subsections.

As you create the files all Part numbers and Section1 numbers will be 1. Then you need to setup the appropriate scheme for each individual file and for each file in the book container. To do this click Format> Document> Numbering in each context. The dialog box should be fairly self-evident. You need to setup the same scheme BOTH for the file itself and for the file entry in the Book. Yes I know it's strange. If you don't get this right, FM will complain about differences between book settings and file settings and propose using book settings to override file settings.

Now to get the numbering updated you need to use Edit> Update Book.

Two disclaimers:
1. The menu names might be wrong because I work in French FM and I don't have a copy of FM in English to check the menu names.
2. This scheme might not work exactly as you want it to work, but it should set you on the right path for now. You may get better advice when some of the experts get back from thanksgiving.
Cheers
Ian