Installing Local RPMs
Sometimes you'll have a .rpm file downloaded directly, rather than from a repository. You can install it with either rum or the Software Center.
Using rum
sudo rum install ./path/to/package.rpm
rum resolves and installs any dependencies the package needs, and adds it to the overlay just like a package from a repository.
Using the Software Center
You can also double click a downloaded .rpm file, or open it from the Software Center's file picker, to install it through a graphical dialog instead of the terminal.