installing postgresql

hi, i'm really having a difficult time setting up postgresql on my home
computer. i have v7.3.2 preinstalled with my OS, but it's really confusing
trying to comprehend it. there's no usr/local/pgsql/ folder - it's really
hard to find files like postgres.conf. the files seem to be all over the
place :( i'd like to just start again & reinstall a new version from scratch.
(do i need to uninstall 7.3.2 first?). here's what i need to able to do (so
that i can simulate labs for a 300-level Database Management course at home):

* create & run a pgsql server
* create & maintain pgsql databases
* JDBC support

could some1 please advise me as to the exact files that i need to download
(ie, version, source/rpm etc) in order to meet my needs. please be as clear
as possible :)

thanx for any help u can offer
sam

comp details:
dell 600m inspiron laptop (1.4GHz, 512RAM)
i686
Redhat 9.0 OS