Installing Postgres - newbie

Hi,

    I am installing Postgres for the first time on my Linux machine , I
found the following  RPM packages for the RedHat 9

postgresql-7.4.6-2PGDG.i686.rpm
postgresql-contrib-7.4.6-2PGDG.i686.rpm
postgresql-devel-7.4.6-2PGDG.i686.rpm
postgresql-docs-7.4.6-2PGDG.i686.rpm
postgresql-jdbc-7.4.6-2PGDG.i686.rpm
postgresql-libs-7.4.6-2PGDG.i686.rpm
postgresql-pl-7.4.6-2PGDG.i686.rpm
postgresql-python-7.4.6-2PGDG.i686.rpm
postgresql-server-7.4.6-2PGDG.i686.rpm
postgresql-tcl-7.4.6-2PGDG.i686.rpm
postgresql-test-7.4.6-2PGDG.i686.rpm

    How do i know which one is for installing the Postgres server and
what are the other packages for ? do i have to install all these
packages too ?
Can anyone please tell what these each packages are for ?


Thanks!
Pallav