[ADMIN] create postgres superuser?

[hoelc]

Hello,
I'm a newbei in this Unix world.  I've a simple question here that need some
advise.
How should I create postgres superuser?
I'm currently trying to install PostgreSQL into my Linux system, and the
Installation Procedure stated that we need to create the Postgres superuser
account.  I wonder, by just "adduser" with user ID as postgres is enough?  Or is
there other steps that I should do?
Please advise.  Thank you very much.
Regards,
LCH