The main steps are the following (details below---this steps are general and should be useful also for operating system different from ubuntu, e.g., Windows and Mac OS):

(1) install postgresql (a database and a user are created, both named "postgres")
(2) assign a password (e.g., "postgres") to the "postgres" user
(3) install pgadmin, preferably version 3 (this is not strictly necessary but it is much more user-friendly to use pgadmin to connect to the postgres server than the command-line client "psql")
(4) add a connection to the postgresql server inside pgadmin


================================================================================


In what follows, some more detailed instructions about some of the steps above.
Most of the these instructions are specific for ubuntu-like operating systems

------------------------------
Step 1: install postgres
------------------------------

- use the following command:
sudo apt-get install postgresql postgresql-contrib postgresql-common


------------------------------
Step 2: set-up postgres (assign a password to the "postgres" user)
------------------------------

- use the following command to launch the "psql" client:
sudo -u postgres psql

- when inside the "psql" client execute the following instruction:
ALTER USER postgres PASSWORD 'postgres';

- to exit the "psql" client execute the following instruction:
\q


------------------------------
Step 3: install pgadmin, preferably version 3
------------------------------

- use the following command:
sudo apt install pgadmin3


------------------------------
Step 4: add a connection to the postgresql server inside pgadmin
------------------------------

- click on the button in the top-left corner ("Add a connection to a server")
- in the "New Server Registration" window, add the following data:
  -- Name: <anything you like>
  -- Host: 127.0.0.1
  -- Port: 5432
  -- Maintenance DB: postgres
  -- Username: postgres
  -- Password: postgres
  and then click "OK"
- if a "Saving passwords" warning appears, just click "OK"
- if a new window appears asking to fix some issues related to some missing packages, just click "Fix it!"


================================================================================


In what follows, instructions to uninstall postgresql and pgadmin (only for ubuntu-like operating systems)

------------------------------
uninstall postgres
------------------------------

- use the following command:
sudo apt remove --purge postgresql postgresql-common


------------------------------
uninstall pgadmin, version 3
------------------------------

- use the following command:
sudo apt remove --purge pgadmin3


================================================================================


In what follows, instructions to make a backup (dump) and then restore a database (only for linux-based operating systems)

------------------------------
DB backup
------------------------------
We assume a postgres server is installed on the local machine and we want to make a backup copy of the database named "postgres" (the whole database, not a single schema).
We also assume an username "postgres" exists on the postgres server.
We also assume folder "/home/dario/Desktop/backup/postgres.sql" to exist and user "postgres" has write (w) and execution (x) permissions on it.
------------------------------

- use the following commands:
sudo su - postgres
pg_dump -U postgres -W postgres > /home/dario/Desktop/backup/postgres.sql


------------------------------
DB restore
------------------------------
We assume we want to restore a database stored in the file "/home/dario/Desktop/backup/postgres.sql" using the method described above.
The new database will ba called "postgres_backup".
------------------------------

- use the following commands:
sudo su - postgres
psql -U postgres -W --command="create database postgres_backup"
psql -U postgres -W postgres_backup < /home/dario/Desktop/backup/postgres.sql