If you're running the GNOME or KDE GUI desktop environments, just place the CD in your CD-ROM drive. You'll be prompted for the root password (you need to be root in order to install packages). After you type in the root password, either the Gnome-RPM or the Kpackage package management program will start automatically and can be used to install PowerTools.
See Chapter 6 for specific instructions on how to use Gnome-RPM. See http://www.general.uwa.edu.au/u/toivo/kpackage/ for more information on how to use Kpackage.
If you're not running GNOME or KDE, you'll need to use RPM to install PowerTools. See the section called If You're Not Running GNOME or KDE for more information on how to install PowerTools if you're not running GNOME or KDE.