I want to have the map of the Hidden Object game, when the player is near the object and it press the letter "Q". The object is revealed to the player.

Put a script on your object. Anything under 'showDistance' will show the object. Untested.

 var showDistance = 3.0;
 private var goPlayer : GameObject;
 
 function Start() {
     goPlayer = GameObject.Find("Player");  // Assumes the player is named "Player"
 }
  
 function Update () {
     renderer.enabled = ((goPlayer.transform.position - transform.position).magnitude < showDistance);
 }

robertbu, and now how do I run this function so if I click a certain button