How to make something like, 3, 2, 1 Go!

Hello im newbie and i dont know how i can make something like a start screen that counts

3, 2, 1, Go!

and then the game start?

Thanks

as @Mortoc said, do lots of tutorials, from Unity and any you can find : http://answers.unity3d.com/questions/12321/how-can-i-start-learning-unity-fast-list-of-tutori.html

Also, use the search bar (top right) to search this 'site, just reading some answers will help you learn.

For your question, here’s an edit of an answer I did for a similar question : : http://answers.unity3d.com/questions/212012/how-to-add-texture.html

It uses 2 main commands :

GUI : http://docs.unity3d.com/Documentation/ScriptReference/GUI.html

and yield : http://docs.unity3d.com/Documentation/ScriptReference/WaitForSeconds.html

Here is the script. To start the counter, call the function getReady()

// variables
private var countdown : String = "";    
private var showCountdown : boolean = false;


// call this function to display countdown
function getReady ()    
{
	showCountdown = true;    

	countdown = "3";    
	yield WaitForSeconds (1.5);  

	countdown = "2";    
	yield WaitForSeconds (1.5);

	countdown = "1";    
	yield WaitForSeconds (1.5);

	countdown = "GO";    
	yield WaitForSeconds (1.5);
   
	showCountdown = false;
	countdown = "";  
}

// GUI
function OnGUI ()
{
	if (showCountdown)
	{    
		GUI.color = Color.red;    
		GUI.Box (Rect (Screen.width / 2 - 100, 50, 200, 175), "GET READY");

		// display countdown    
		GUI.color = Color.white;    
		GUI.Box (Rect (Screen.width / 2 - 90, 75, 180, 140), countdown);
	}    
}