Postgresql 7.x

I need to get postgresql running on a redhat 7.2 server to get a php
database up and running.

I am having problems configuring the postgresql.conf bg_hba.conf and the
other files in the /var/lib/pgsql/data

The situation is -

The server is running interchange and virtually hosting 4 domains for the
same person. I don't know how to configure postgresql so any help woul be
great.

I believe postgresql 7.1.x is installed already

-Dan