BUG #16203: So difficult to set an use postgres

The following bug has been logged on the website:

Bug reference: 16203
Logged by: Reyna Melara
Email address: remabarca(at)gmail(dot)com
PostgreSQL version: 11.0
Operating system: Debian Jessie
Description:

Hi, I've trying for several hours to set, configure and use postgres in any
of my debian operating systems. It seems it has been installed properly but
then when I wanted to use PgAdmin it keep telling me it could not establish
the connection, in my laptop also with debian it was not possible to use any
pgAdmin not 3 nor 4. I have followed the instructions form the official page
and t possible.
Now that In my PC could finally use postgres and also pgAdmin I can't use
unqualified names, I have to use the public schema or my own schemas with
qualified names, I have also followed the manual instructions and it it not
possible, it keep telling me that my relations does not exists.
Maybe the instructions are for so much more specialized users, but I can
tell that there is a big group of students that sometimes can't find the
instructions easy, specially when we are not Windows users.