In order to use refdb-mode and the associated ris-mode you'll have to load these modes either from your .emacs or from a global startup file (default.el or site-start.el). To this end, load the configuration file from one of the startup files like this:
(load-file "/usr/local/etc/refdb-mode-config.el")
Alternatively, you can copy the code in that file directly into one of your startup files. Please see the comments in the example configuration file for further instructions.
Some package management systems use a site-start.d directory which holds this kind of Emacs startup files. You can put an appropriately named symlink to refdb-mode-config.el into this directory.