rpm -ivh *.rpm
in a directory which contains only the OpenVL packages. If you are upgrading from an earlier version of OpenVL already installed on your system, then use:
rpm -Uvh *.rpm
This removes earlier versions of OpenVL and installs the new version.
You can also install/upgrade from inside the konqueror file manager. Just click on the RPM packages you downloaded one by one and install/upgrade them. You will always need to install/upgrade the libopenvl package before the libopenvl-devel and libopenvl-plugins packages.
Note that it is possible to install multiple unstable releases of OpenVL with different major and minor version numbers at the same time. However, you can only have one installation of unstable releases with the same major and minor version numbers. Similarly, you can only have one installation of stable releases with same major version number. You will only be able to upgrade between these releases. Since these releases maintain binary compatibility, an upgrade should not cause any problems.