Simply put, to install WinRar on Fedora:
rpm -ivh http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm yum install unrar
The first command adds rpmfusion into your yum repository. Then, the yum command installs unrar from rpmfusion. Now you can extract rar files by ‘unrar e filename’. During the installation of unrar, yum may prompt you if it is OK to import GPG key from RPM Fusion nonfree repository? Type y to add it.
WinRAR is provided by RARLAB. Its download page points to rpm.livna.org for Linux version unrar. However, livna has been merged to rpmfusion. Thus, you should add rpmfusion into your yum repository instead. To do that, either follow the section “command line setup using rpm” on its config page or only add the nonfree repository (WinRAR is not open sourced) as I did above.