HTML to EPUB how to set up chapters

[sum1doe]

I'm making a personal use downloader for a site I use, which currently spits out html (shouldn't be difficult to change into anything else, but that might break anything non plaintext, should the authors use a table or whatnot).

I am saving these into files, chapter by chapter, and converting them to epub by chapter1, chapter2, etc in the command.

Upon conversion to epub, these do not show up with anything fancy; it's all just one long bit plain text. How does one set up the chapter file such that it works?

[sum1doe]

for reference, the chapter.html files are currently structured as follows:

<p>Text here</p>
<p>New Line</p>

[jgm]

You need section headings (e.g. <h1>Chapter one</h1>). See docs for --split-level.

[sum1doe]

Thank you kindly!