Can anyone point me to docs / tutorial on setting up launcher to auto-update osquery? I vaguely remember there being some step-by-step tutorials when I looked a year or so ago but I'm struggling to find them today. Like, something that shows which infrastructure pieces (e.g., Notary) are required / how to configure and start things.

Launcher uses notary. Notary doesn’t serve files, just signatures. Files are served by an http server somewhere. So, you need those two things.