School teacher in need of HELP

Hello,
I have no IT experience and no funding to hire a technical person or resources to take a training course. Also my friends who have programming background have not been reliable. I am willing to spend the necessary months in trying to learn how to use an SQL program. I just installed PostgresSQL 9.0. While trying to read through the documentation I proceeded to chpt. 1.3 Creating a Database, which commands I followed. Chpt. 1.4 Accessing a Datebase commands are confusing. I tried to enter the commands on the SQL Shell(psql) from which line 1 reads Server [localhost], line 2 –Database[postgres]: and I entered postgres, line 3 – Port[____], which number I entered), line 4 - Username[postgres], where I entered postgres, line 5 Password for the postres: ....... which returned the message FATAL : password authentication failed for user “postgres”..... Press any key to continue.

Can you help me understand how to start accessing the server database capabilities and/or mention on online support blog.

Thanking you in advance,
Hilary