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@gmail.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