Can't assign camerarig as child of instantiated players,Can't parent camerarig object to instantiated players.

I am new to Unity and coding in general, I did the TANKS! tutorial from 2015, and made a copy of the game with custom models, but I want to implement a split-screen camera instead of the top-down two-player setup. I have already set up the two cameras and they are following and looking at two empty objects. I want to assign these empty game objects as children of the player tanks as they spawn in. using System.Collections; using System.Collections.Generic; using UnityEngine;

public class TankParentToCaemraRig : MonoBehaviour {

 public GameObject CameraRig1;
 public GameObject CameraRig2;

 // Start is called before the first frame update
 void Start()
 {
     if (GameObject.Find("GameManager").GetComponent<TankManager>().m_PlayerNumber == 1)
     {
         CameraRig1.transform.parent = this.transform;
     }   
     if (GameObject.Find("GameManager").GetComponent<TankManager>().m_PlayerNumber == 2)
     {
         CameraRig2.transform.parent = this.transform;
     }
 }

 // Update is called once per frame
 void Update()
 {
     
 }

}

Above is the code I came up with to achieve this, but it's not working and showing me a null exception error. Earlier it was showing this error - ArgumentException: GetComponent requires that the requested component 'GameObject' derives from Mono. The code used to instantiate the tank prefab is using System; using UnityEngine;

[Serializable] public class TankManager { public Color m_PlayerColor;
public Transform m_SpawnPoint;
[HideInInspector] public int m_PlayerNumber;
[HideInInspector] public string m_ColoredPlayerText; [HideInInspector] public GameObject m_Instance;
[HideInInspector] public int m_Wins;

 private TankMovement m_Movement;       
 private TankShooting m_Shooting;
 private GameObject m_CanvasGameObject;


 public void Setup()
 {
     m_Movement = m_Instance.GetComponent<TankMovement>();
     m_Shooting = m_Instance.GetComponent<TankShooting>();
     m_CanvasGameObject = m_Instance.GetComponentInChildren<Canvas>().gameObject;

     m_Movement.m_PlayerNumber = m_PlayerNumber;
     m_Shooting.m_PlayerNumber = m_PlayerNumber;

     m_ColoredPlayerText = "<color=#" + ColorUtility.ToHtmlStringRGB(m_PlayerColor) + ">PLAYER " + m_PlayerNumber + "</color>";

     MeshRenderer[] renderers = m_Instance.GetComponentsInChildren<MeshRenderer>();

     for (int i = 0; i < renderers.Length; i++)
     {
         renderers[i].material.color = m_PlayerColor;
     }
 }


 public void DisableControl()
 {
     m_Movement.enabled = false;
     m_Shooting.enabled = false;

     m_CanvasGameObject.SetActive(false);
 }


 public void EnableControl()
 {
     m_Movement.enabled = true;
     m_Shooting.enabled = true;

     m_CanvasGameObject.SetActive(true);
 }


 public void Reset()
 {
     m_Instance.transform.position = m_SpawnPoint.position;
     m_Instance.transform.rotation = m_SpawnPoint.rotation;

     m_Instance.SetActive(false);
     m_Instance.SetActive(true);
 }

}

,I am new to Unity and coding in general, I did the TANKS! tutorial from 2015, and made a copy of the game with custom models, but I want to implement a split-screen camera instead of the top-down two-player setup. I have already set up the two cameras and they are following and looking at two empty objects. I want to assign these empty game objects as children of the player tanks as they spawn in. using System.Collections; using System.Collections.Generic; using UnityEngine;

public class TankParentToCaemraRig : MonoBehaviour {

 public GameObject CameraRig1;
 public GameObject CameraRig2;

 // Start is called before the first frame update
 void Start()
 {
     if (GameObject.Find("GameManager").GetComponent<TankManager>().m_PlayerNumber == 1)
     {
         CameraRig1.transform.parent = this.transform;
     }   
     if (GameObject.Find("GameManager").GetComponent<TankManager>().m_PlayerNumber == 2)
     {
         CameraRig2.transform.parent = this.transform;
     }
 }

 // Update is called once per frame
 void Update()
 {
     
 }

}

Above is the code I came up with to achieve this, but it's not working and showing me a null exception error. Earlier it was showing this error - ArgumentException: GetComponent requires that the requested component 'GameObject' derives from Mono. The code used to instantiate the tank prefab is using System; using UnityEngine;

[Serializable] public class TankManager { public Color m_PlayerColor;
public Transform m_SpawnPoint;
[HideInInspector] public int m_PlayerNumber;
[HideInInspector] public string m_ColoredPlayerText; [HideInInspector] public GameObject m_Instance;
[HideInInspector] public int m_Wins;

 private TankMovement m_Movement;       
 private TankShooting m_Shooting;
 private GameObject m_CanvasGameObject;


 public void Setup()
 {
     m_Movement = m_Instance.GetComponent<TankMovement>();
     m_Shooting = m_Instance.GetComponent<TankShooting>();
     m_CanvasGameObject = m_Instance.GetComponentInChildren<Canvas>().gameObject;

     m_Movement.m_PlayerNumber = m_PlayerNumber;
     m_Shooting.m_PlayerNumber = m_PlayerNumber;

     m_ColoredPlayerText = "<color=#" + ColorUtility.ToHtmlStringRGB(m_PlayerColor) + ">PLAYER " + m_PlayerNumber + "</color>";

     MeshRenderer[] renderers = m_Instance.GetComponentsInChildren<MeshRenderer>();

     for (int i = 0; i < renderers.Length; i++)
     {
         renderers[i].material.color = m_PlayerColor;
     }
 }


 public void DisableControl()
 {
     m_Movement.enabled = false;
     m_Shooting.enabled = false;

     m_CanvasGameObject.SetActive(false);
 }


 public void EnableControl()
 {
     m_Movement.enabled = true;
     m_Shooting.enabled = true;

     m_CanvasGameObject.SetActive(true);
 }


 public void Reset()
 {
     m_Instance.transform.position = m_SpawnPoint.position;
     m_Instance.transform.rotation = m_SpawnPoint.rotation;

     m_Instance.SetActive(false);
     m_Instance.SetActive(true);
 }

}