The V-Ray installer for SketchUp is straightforward and easy to follow. It can be downloaded from the V-Ray | Downloads section of the Chaos Group website (please make sure you use your login credentials to ensure access to the download links). Before installing V-Ray, it is recommended to check that your computer meets the System Requirements for running SketchUp with V-Ray. If you would like a step-by-step guide, please check out the Installation of V-Ray for SketchUp page.
Once V-Ray is installed you will want to make sure that your V-Ray license is properly configured. The Set up your V-Ray License page includes everything you need to get V-Ray licensed and running properly.
In order to use V-Ray plugin, the render package must be enabled.
SketchUp 2017 and 2018: Window > Extension Manager > Enable V-Ray for SketchUp extension
SketchUp 2016: Window > Preferences > Extensions > V-Ray For Sketchup