URPMI is the package manager for Mandriva. There are many sources for software packages. What is recommended, is to use .mkd packages for Mandriva. All the dependencies are looked after for you. Basically all you do from MCC is select the inatall software option, select the package you want, and install it. It is that easy. Sources can be your install CD ( DVD ) or line repos. The best option are the online repos, the latest versions of programs are located there, along with updates.
For speed a high speed connection is best. Downloading using dial up may take a while. It will work, but be patient.
Go to this link -->http://mandrivausers.org/easyurpmi/index.php
and follow the instructions. Add one repo at a time. Add Main, Contrib, PLF-free, Plf-nonfree, Main-updates, and contrib-updates. There are more, but until you have a better understanding of what you are doing, that should get you most things.
Post back if you need guidance, other than what you find on that page.