(C#)Place GameObject from Mouse

Hello Unity Community. What I am trying to to is place a gameobject if it is less or equal to "X".

Here is my script.

 using UnityEngine;
 using System.Collections;
 
 public class PlaceObject : MonoBehaviour 
 {
     public GameObject Player;
     public GameObject Test;
 
     private Vector3 BuildDis;
 
     void Update () 
     {
         BuildDis.x = Player.transform.position.x + 10;
 
 
         if(Input.GetKey(KeyCode.Mouse0))
         {
             if(Input.mousePosition.x <= BuildDis.x)
             {
                 Vector3 MousePos = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y,0.0f));
                 
                 Instantiate(Test, new Vector3(MousePos.x, MousePos.y, 0.0f), Quaternion.identity);
             }
         }
     }
 }


 

I do not get any errors but it does not work.

Thanks for the help in advanced :D