Just simply install the plug-in.
If you are on Mac, then it’s simple, because there are strict folders, where has to be the plug-in installed. So you can just launch Cubase, and the plug-in should appears.
If you are on Mac, I would recommend to trail the installation. There should be information displayed, which says, where is the VST plug-in (DLL file) stored. Then open Cubase, open Plug-in Manager from Devices menu, click to the Plug-in Manager Settings button, then to the + (Add Path) button, and add the folder, where is the DLL file installed, to the list. Update the list. Your plug-in should appears.