VRscans does not need to be installed and is already installed with the typical V-Ray installation. VRscans does need a separate license for that plugin specifically, however, as its license is different than that of V-Ray itself. More information on obtaining a license for VRscans is found here.
VRscans Platforms
VRscans is installed with V-Ray on the following platforms:
Here we talk about how to set up the license or macro in the OLS license methodology, or whatever is needed to explain license setup.