I can't install gcc

[Nirgal]

Greetings

I work on SuSE Linux 7.0 and I need to install fortran compiler which I
didn't find in my distribution. There is only gcc. In spite of having gcc
already I downloaded "gcc-core-2.95.3" and "gcc-g77-2,95,3". I found there
some instructions about installing the software, but it's too general for me
(by the way I'm a beginner in Linux). Before I downloaded "gcc-2.95.3" I
could read instructions from "gcc-2.7.2" and there are step by step ones. If
you wrote me how to install "gcc-g77-2.95.3" step by step I'd be thankful.

Nirgal
            - student of astrophysics (this is what for i need fortran and
pgplot soon)