Fix and configure postgresql on debian 9

I'm unable to use postgresql on debian I installed the next packages : sudo apt-get install -y postgresql-9.6 postgresql-contrib-9.6 sudo apt-get install -y postgresql-doc-9.6 postgresql-server-dev-9.6 But I don't know how to add the root user and I can't create or login new users. I use Adminer on [login to view URL] I will provide the ssh access codes and you can drop the db and reinstall postgresql with apt-get Thanks, Pepe