AudioClip management by script with Unity 5

Before, with Unity 4.6, I was using the following script, to manage the activation of AudioClip sound effects:

 var positiveSound : AudioClip;
 var negativeSound : AudioClip;
 
 function OnGUI ()
 {
  if(GUILayout.Button(PositiveTexture))
  {
    audio.clip = positiveSound;
    audio.Play();
  }
  if(GUILayout.Button(NegativeTexture))
  {
    audio.clip = negativeSound;
    audio.Play();
  }
 }

Now, Unity is telling me that this kind of code is obsolet and I need to replace it with GetComponent(AudioSource); , so I replaced the first part audio.clip = positiveSound; with GetComponent("positiveSound"); to find the necessary AudioClip, but once I've found it, how do I play it? I tried many combinations, but no one worked. I tried to search the site for an answer to my problem, but I keep finding only pre-Unity 5 tutorials and instructions.