Im kind of confused about the UI in Unity 4.6

Im very confused, I decided id watch a tutorial on Unity’s UI. So I added a button, but the button is always there… How do I make it so the button is only there when the game is started? Id like to make it so when the game is started, you see the button, but then when you press it, the game starts, and then the button goes away
Could anybody please direct me to a good Unity UI tutorial? Thanks

create a empty game object and write this script for that :

var StartButton:GameObject; //your ui button

function Start { Time.timeScale = 0.0; } //stop the game

function GameStart()
{ Time.timeScale = 1.0; StartButton.SetActive(false); } //resume the game and deactive the button(hide it)

then in your ui button assign GameStart() function to Onclick .