Postgres Initial Setup and User Login Full disclosure, new to postgres and new to linux. I am having trouble understanding the user management side of postgresql. I installed on a Ubuntu 19.04 based os using 

sudo apt update
 sudo apt install postgresql postgresql-contrib


Ive been able to switch to the default user postgres and can successfully call psql amongst other commands. When trying to connect via pgadminIII i am prompted for a password when using the same user name. A couple searches reveal that you should be able to leave this blank. I get an error stating no password supplied. 

Additionally, I would like to make my own user name an admin and use my linux password. I suppose this would be similiar to windows authentiaction on microsoft sql. After searching the internet it appeared that all i need to do is createuser *MyNameHere* and declare it a superuser. However when atempting to connect form command line it acts like there should also be a database named the same as my user. Secondly when using the pgadmin it actively rejects my credentials.

I guess my question is this:

Can someone explain to me the basic concepts of roles/usernames and how they relate to the linux user names. And secondly, what is going wrong in the above.
Users, roles, and permissions can get kind of confusing in PostgreSQL. To control who can try to connect to the database, Postgres uses the pg_hba.conf file. In Ubuntu, it's buried in /etc/postgres/&lt;#>/main.

From inside the data base there are roles which control permissions each user has inside the database.

An easy, but probably insecure way to connect is to set up trust from localhost connections in pg_hba.conf.