Well now that I see it is just the "tutorial" in the official docs, I disagree that is the correct place to start. At least not if it is going to ship with the 1000+ pages of documentation we already have. What I am envisioning is something with a strong SEO that gives pointed and direct information about solving a specific problem. A tutorial book could certainly do that as could (what I am really talking about) is Postgres recipes or something like that.
I didn't know it existed either, mostly because I know how to ask google to do things, and the things I need to know are not covered here (yet). This does seem to me to be the ideal place to add more how to documentation to augment all the reference docs we have.
As for some "strong SEO" I think already the top hit for almost everything I seek postgres related is the official manual, so it seems to have good SEO. The only big improvement would be somehow to tell google to only show me the newest version of the manual, not all of the older ones too, for the same page.