Unity3D is a complex engine, but it's very easy to get started with. In this section, we'll cover every aspect of the engine you need in order to build and deploy your first VR experience, but we'll be exploring different capabilities of the engine every chapter. Unity3D offers support for a few different languages, but all code we write in this book will be C#.
To install Unity, navigate to http://www.unity3d.com/ and download the installation assistant from the front page. Unity offers a Personal and Professional edition; the Personal edition is free and contains everything you need to create a VR application. Also, create a Unity account on the page to manage your license and other account-based services.