Unpack plugin in Cinema4D Rxx\Plugins directory. Start Cinema4D and open Options window: Plugins > RizomUV Exporter > Options Specify the work path of the rizomuv.exe ( default location is: C:\Program Files\Rizom Lab[RizomUV] )
If you are updating the plugin, please, delete the settings.json ( the previous version's configuration file ) file from C:\Users[USER]\AppData\Roaming\MAXON\Cinema 4D R1X_XXX\prefs\rizomUV folder.