Installing Programs through KPackageKit
In order to install from KPackageKit, you will need to go to the "K" button, then click on Applications, System, KPackageKit. Then you will enter the package name in the search field and search for it. You may want to refresh the lists prior to this. Once you find the package(s) that you wish to install, you will click the down arrow on the right-hand side. After selecting all of the packages that you want to install, you click the Apply button.
If the packages have dependencies, you will be presented with a list of them and the option to "Mark" or "Cancel". "Marking" will select them for installation as well. Then the installation will download the files, and install them. Depending on the packages, you may have to log out and back in (restart "X"), or restart the computer.
If you're not sure about the package name, you can search in the description for the common name. For example, "Open Office" is the common name, but the actual package name is openoffice... So, you would have to search for "Open Office" in the description or openoffice in the package name.