How do i change Cinemachine's LookAt and Follow from a script?

So, first of all, i am pretty new to unity, and I am trying to create a multiplayer game using photon.
I have a script that spawns two players at the start of the scene, and I need to use them as the LookAt and Follow, but I keep getting back this error:

NullReferenceException: Object reference not set to an instance of an object
it refers to the spawning script:

Code (CSharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using Photon.Pun;
5. using UnityEngine;
6. using Cinemachine;
7.  
8. public class PlayerSpawner : MonoBehaviour
9. {
10.     [SerializeField] private GameObject playerPrefab = null;
11.     [SerializeField] private CinemachineFreeLook playerCamera = null;
12.  
13.     private void Start()
14.     {
15. //spawn player
16.         var player = PhotonNetwork.Instantiate(playerPrefab.name, Vector3.zero, Quaternion.identity);
17.  
18. //connect Cinemachine
19.         playerCamera.Follow = player.transform;
20.         playerCamera.LookAt = player.transform;
21.     }
22. }
23.  

 

I am developing a new response to this most-common question:

http://plbm.com/?p=221

Feedback and comments to that post are always welcome.

 

you dont have a 'GameObject' assigned to 'playerPrefab'