By default, in5 will export all of the pages in your document.
In the Basic section of the export dialog (in5 > Export HTML5 with in5...), you can choose a Custom range.
The syntax is the same as exporting a page range to PDF:
- Use a dash (-) to denote a range (e.g., 1-5 assuming page 1 is named 1)
- Use a plus (+) to reference an absolute page position (e.g., +1-+5)—this is useful when you're pages have custom names (e.g., Aii, Bvi, etc).
- Use commas (,) to choose individual pages (e.g. 1,2,4)
When your document contains multiple layouts, you will also see those layouts in the Export Range dialog. To export a single Alternate Layout, choose that layout from the Export Range menu.