How do i add a prefab into my game using code?

I am having issues with my script where i wan't to add a prefab called "Wall" into the game using the player current position but the script will not add the prefab into the game.

Here is my code:
//Variables
public GameObject Wall;
public GameObject Floor;
public GameObject BuildingUI;
private bool MenuActive = false;
public GameObject Player;
public void Start()
{
Wall.transform.localPosition = Player.transform.localPosition;
}
public void Update()
{
if (Input.GetKeyDown(KeyCode.B))
{
if (MenuActive == false)
{
MenuTrue();
} else
{
MenuFalse();
}
}
if (WallSelected == true && tag == "Player")
{
ImportWall();
}
}
public void MenuTrue()
{
GameObject.Find("Player").GetComponent<FirstPersonController>().enabled = false;
BuildingUI.SetActive(true);
Time.timeScale = 0f;
Cursor.visible = true;
Cursor.lockState = CursorLockMode.None;
MenuActive = true;
}
public void MenuFalse()
{
GameObject.Find("Player").GetComponent<FirstPersonController>().enabled = true;
BuildingUI.SetActive(false);
Time.timeScale = 1f;
Cursor.visible = false;
Cursor.lockState = CursorLockMode.Locked;
MenuActive = false;
}
public void ImportWall()
{

}
----------------------------------------------------------
Any help would be very helpful, Thankyou Nick

 

You're using "Wall" in the Start() method, so you must have dragged a reference in the Inspector. Otherwise it would be null and you would get errors.

If you drag a prefab from the Project view into the value for Wall, then it is a valid prefab reference. You don't want to position the Wall which is a prefab reference, because it's not really part of your Scene. You want to Instantiate(Wall,...) to make a clone of the prefab into the Scene. Then you can move the clone around.

But I also notice you're trying to set the wall's .localPosition, which doesn't do what you think it does. To position things in the Scene, you want to be working with the .position instead of .localPosition field.

 

Thanks that worked, but how would i reference its position to equal the players position?