V-Ray is a renderer plugin for SketchUp. In order to use V-Ray, you must first select it as your current renderer. You can do that by clicking on the Windows menu, choosing Preferences. In the System Preferences window choose Extensions and make sure that V-Ray for SketchUp is selected from the  menu:

The V-Ray parameters are divided into several tabs in the render scene dialog; additionally each tab is divided into several rollouts: