Unity UI Basics—Getting Started
As you are probably pretty anxious to get started creating something in Unity, the introduction to Unity’s UI (user interface) will be kept rather brief. You will explore and investigate it more fully as the need arises, but for now, you can get a basic feel for the layout options and concepts. If you’d like to delve further into the UI before moving on, the Unity help files include a very good section on getting started.
Installing Unity and Starting Up
Download Unity from http://unity3d.com/unity/download/ and install it. The Unity icon will appear on your desktop when the installation is complete ...