This HOWTO is currently written with LyX version 2.2.2 on a Fedora 25 Linux system with template SGML/XML (DocBook book). It's available on github / tLDP / Linux-IPv6 for contribution.
Code line wrapping is done using selfmade utility ”lyxcodelinewrapper.pl”, you can get it from GitHub for your own usage: github / tLDP / Linux-IPv6
SGML/XML is generated using export function in LyX.
Generally, a reference to the master index page is recommended.
Because the HTML pages are generated out of the SGML file, the HTML filenames turn out to be quite random. However, some pages are tagged in LyX, resulting in static names. These tags are useful for references and shouldn't be changed in the future.
If you think that I have forgotten a tag, please let me know, and I will add it.