To install a plug-in drag it into the "Plugin" folder nested inside the CINEMA 4D folder.
Plug-ins can be added while CINEMA 4D is running simply by placing them in the "Plugin" folder and choosing the "Reload" command from the Plug-in submenu in the Tools menu.
Please find more information and help at Gumption PlugWare - Maxon Computer’s offical service partner under http://www.gumption.de