UnassignedReferenceException: The variable Player of TapToDisplay has not been assigned.
You probably need to assign the Player variable of the TapToDisplay script in the inspector.
TapToDisplay.Update () (at Assets/Scripts/TapToDisplay.cs:12)

public class TapToDisplay : MonoBehaviour
{
    public GameObject PlayerObject;
    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            PlayerObject.transform.Translate(new Vector2(1,0)*Time.deltaTime);
        }else if (Input.GetMouseButtonUp(0))
        {
         PlayerObject.transform.Translate(new Vector2(-1,0)*Time.deltaTime);
        }
    }
}