Getting Started: Tutorials/Books?

Greetings, all.

I am getting started with only basic computer-using skills and essentially
no programming knowledge. I am in need of a tutorial and/or a reference
book that will help me learn to use pgAdmin III.

The tutorial that exists in the help file appears to focus on using the psql
program from within a command shell. I have failed to accomplish even the
most basic commands in this manner; the system tells me that user "emc" does
not exist, I do not appear able to create that user, and I cannot see a way
to switch to a valid user. Meanwhile, using pgAdmin III, I appear to be
able to create new databases and tables.

I am assuming that my gross lack of knowledge is what keeps me from using
the command shell while I can make use of the pgAdmin III interface. The
interface is clearly picking up the slack for me, which I appreciate.

This does not help me get beyond the wall of incomprehension at the next
stage, though. I can spawn a database, and I can create a table. I do not
grasp the basics of table mechanics from the programming side. (I have, on
paper, the table I want to create; I do not know how to make this happen in
the database.)

Is there a comprehensive tutorial available for this, or can you recommend a
book that can give me the background knowledge I need to begin to make
progress?

- emc