Instantiate a prefab with a key press to a relative location?

I added this in where I thought I am supposed to, but I keep getting errors no matter what I change.

 #pragma strict
 
 var objectName : GameObject;
 var player : GameObject;
 function Start()
 {
    
     
 }
 
 function Update()
 {
 if(Input.GetKeyDown(KeyCode.X)) {
 pos : Vector3(player.transform.position.x+15,player.transform.position.y+1.5,0);
      var rot : Quaternion = Quaternion.identity; 
      Instantiate(objectName, pos, rot);
 }
 }

It's telling me that pos is an unexpected token. I added the variable "player", because I was getting some other error. Also, what is "player" in "player.transform.position" a reference to? Is that where the name of the player is supposed to be? Because the name of the player gameobject is Character and is tagged as Player. Sorry, I'm just bad at this.

Make sure you have dragged your player into the player field in Inspector; the name or tag is irrelevant. I don't do JS but maybe you need the keyword 'var' in front of the pos = ... bit

 if(Input.GetKeyDown(KeyCode.X)) {
 var pos : Vector3;((player.transform.position.x+15) (player.transform.position.y+1.5,0));
      var rot : Quaternion = Quaternion.identity; // Quaternion.identity essentially means "no rotation"
      Instantiate(objectName, pos, rot);
 }
 }

I added var and then it said I needed a semi colon after Vector3 and then it didn't like the comma and lack of parenthesis. So, this is what it looks like now and it's saying " It is not possible to invoke an expression of type 'float'". Hmmm it's getting late so I'm gonna have to sleep on this, but what did you mean by "dragged your player into the player field in Inspector"?

You put a semi-colon after Vector3, remove that; you put parenthesis around the Vector3 arguments, undo all that; I can't really teach you JS syntax line by line in this space, some basics are assumed/needed.

Regarding player, you setup a variable named player when you added the line var player : GameObject;

In the Inspector, if you look at the GameObject this script is attached to you'll see a field named player; drag your Player (from the Project hierarchy/windows next to scene) into that field. Again, that's pretty much Unity Day 1 app basics, you might really benefit from a few tutorials - I wish you luck.

Finally got it, thanks a ton!

 #pragma strict
  
 var objectName : GameObject;
 var player : GameObject;
 function Start()
 {
  
  
 }
  
 function Update()
 {
 if(Input.GetKeyDown(KeyCode.X)) {
 var pos = Vector2(15,2); 
      var rot : Quaternion = Quaternion.identity; 
      Instantiate(objectName,pos+player.transform.position, rot);
 }
 }

Link to my other question with same problem: http://answers.unity3d.com/questions/660701/instantiate-to-relative-location.html