how to wait time in unity code example

Example 1: Time delay C# unity

void start()
StartCoroutine(Text());

IEnumerator Text()  //  <-  its a standalone method
{
	Debug.Log("Hello")
    yield return new WaitForSeconds(3)
    Debug.Log("ByeBye")
}

Example 2: waitforseconds unity

public void GameOver()
		{
			//Set levelText to display number of levels passed and game over message
			levelText.text = "After " + level + " months, you starved.";

			new WaitForSeconds(6);

			Application.Quit();


		}