He’s probably talking about a third party guide by @tempest.
Main link:
https://anonguide.cyberguerrilla.org/
chapter:
https://anonguide.cyberguerrilla.org/c4g.html
It was also posted in Whonix forums back then:
https://forums.whonix.org/t/comprehensive-guide-to-installing-and-using-a-safer-anonymous-os