The \c ## comes before the \s xxxx in the SFM, but PtxPrint puts the Chapter number larger and inline with the first paragraph after the section heading.
If you want a heading-like chapter like “Chapter 1”, then you can put:
\cl Chapter
before \c 1 in the USFM.
If you want the order different, something more like Hungarian’s
“1. Fejezet”, where the number comes before the chapter, then in `ptxprint-mods.tex" you would also put:
\def\MakeChapterLabel#1#2{#2. #1}
If you want to just have the number, then the \cl line could be, for instance \ZWNBSP (zero width non-breaking space).
For completeness, if you want The First Chapter as a title, or something similar, then you would put:
There’s actually a place in the UI to control this at the end of the Body tab. The tooltips tell you what to do. Normally this kind of different chapter styling is done for Poetical books (such as PSA and PRO), but if you leave the book list empty, it should apply to all books.
As it expects a “Chapter”-like label, if you don’t put anything in there, it probably won’t do what you’re expecting. So the \ZWNBSP hack puts in an invisible but valid character before the number.
Chapter number between dashes, ignoring any “Psalm” or other \cl contents (but still needing a \cl somethng to trigger it): \def\MakeChapterLabel#1#2{- #2 -}
Including any \cl contents, before the number: \def\MakeChapterLabel#1#2{- #1 #2 -}
Label afterwards, with ‘va’ ‘magically’ appearing after the number: \def\MakeChapterLabel#1#2{#2va #1}
(lets you end up with 2va capitolo, 3va ghili, etc)
In other words, you end up seeing what’s in the curly brackets, and #1 is replaced by the text of the \cl, and #2 by the chapter number.
By the way… if someone wanted TeX to to automatically provide a varying suffix, like English’s 1>1st, 2>2nd 3>3rd, 111-> 111th, 121 → 121st etc. then it gets fairly tricky. First the number would need to be re-interpreted to be a number (as opposed to text, as it is now), and then someone would need to supply the correct logic, or maybe an \ifcase for all values up to 150.