I am a beginner for Unity3d,I want make a menu contains three page or more,who can tell me the logic.I don't know whether you are understand me.like a game menu.please!

http://unity3d.com/support/documentation/Components/GUI%20Scripting%20Guide.html

If that's too much for you then use this package:

http://www.anbsoft.com/middleware/ezgui/

Or this one:

http://forum.unity3d.com/threads/60538-GUIKit001-Plug-Play-Interface-for-all-platforms