Odoo is already running on port and you try to run on same port. There are two option you have
1. Try to run Odoo in another port using --xmlrpc-port 8070 parameter.

$ ./odoo-bin --addons addons/ --xmlrpc-port 8070

2. You need to first kill Odoo service. Use below command to find Odoo service.

$ ps ax|grep odoo
17025 pts/0    Sl+    0:06 python3 ./odoo-bin --addons addons/

Use following command to kill service

$ sudo kill -9 17025

Now you try to run Odoo.

Hi,

You have to follow Step 3 “Setup a PostgreSQL user for Odoo” and “Access PostgreSQL database using pgAdmin III”.

You probably need to read this thread.

If your terminal not asks you for new role then you might need to execute following command to assign superuser rights to new user.

$ sudo su postgres
$ psql

postgres=# \du;
                                    List of roles
 Role name  |                         Attributes                         | 
------------+------------------------------------------------------------+-----
 twink      | Create DB                                                  | {}
 postgres   | Superuser, Create role, Create DB, Replication, Bypass RLS | {}


postgres=# ALTER USER twink WITH SUPERUSER;
ALTER ROLE
postgres=# \du;
                                    List of roles
 Role name  |                         Attributes                         | 
------------+------------------------------------------------------------+-----
 twink      | Superuser, Create DB                                       | {}
 postgres   | Superuser, Create role, Create DB, Replication, Bypass RLS | {}

Try to recoonect PgAdmin again.

Any help?