Loading the V-Ray Shelf
When starting V-Ray for Houdini for the first time, you need to manually load the V-Ray Shelf. From the Houdini shelf, click the plus + icon, navigate to Shelves, and select V-Ray from the list.
Selecting a Renderer
To render with V-Ray, simply click the Render button from the V-Ray Shelf. This automatically creates a vray_renderer node in the Network Editor (if one is not already present) and launches the V-Ray Frame Buffer.