BUG #18547: bemused by your unhelpful installation guides

The following bug has been logged on the website:

Bug reference: 18547
Logged by: Neil Watcyn-Palmer
Email address: nwpnow(at)gmail(dot)com
PostgreSQL version: 16.3
Operating system: truenas
Description:

Hi I am beyond critical of your documentation
My research suggested that Postgresql would install on TRUENAS core see
https://github.com/stualden/postgresql-misc/blob/main/install_postgres_on_truenas.md

When I step through it features claimed in the git hub text are inaccurate
for release 16.3 - the users and user group are NOT created automatically
by the pkg install

When they are manually created and given full access to both source and
destination mount points the error permission denied to a folder
structure not stated in the mount points is returned - what am I to do ?
Read the manual. I have and it is utterly obtuse what to do.
You guys have written it assuming knowledge. I am a film maker using
Davinci Resolve which come with a postgreSQL database setup rather than an
xml file structure. My films files are many and large so XML tends to
creak a little. BUT I cannot use this facility because I cannot get past
your installation "guide"
so I write to explain the frustration and hope you can assist OR at least
tell me that what I am doing is impossible because Postgresql is ot
compatible with TrueNAS-13.0-U6.1