Tell me what I did wrong

I got this error
Assets\leaderboard.cs(34,48): error CS1061: ‘Player’ does not contain a definition for ‘GetScore’ and no accessible extension method ‘GetScore’ accepting a first argument of type ‘Player’ could be found
I used a tutorial I found to try and recreate it but I can’t figure out how to make this work

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Photon.Pun;
using TMPro;
using System.Linq;

public class Leaderboard : MonoBehaviour
{
    public GameObject playerHolder;

    [Header("Options")] 
    public float refreshRate = 1f;

    [Header("UI")] 
    public GameObject[] slots;
    [Space]
    public TextMeshProUGUI[] scoreText;
    public TextMeshProUGUI[] nameText;

    private void Start()
    {
        InvokeRepeating(nameof(Refresh), 1f, refreshRate);
    }

    public void Refresh()
    {
        foreach (var slot in slots)
        {
            slot.SetActive(false);
        }

        if (PhotonNetwork.PlayerList.Length > 0)
        {
            var sortedPlayerList = PhotonNetwork.PlayerList.OrderByDescending(player => player.CustomProperties.ContainsKey("score") ? (int)player.CustomProperties["score"] : 0).ToList();

            int i = 0;
            foreach (var player in sortedPlayerList)
            {
                slots[i].SetActive(true);

                if (string.IsNullOrEmpty(player.NickName))
                    player.NickName = "Unnamed";

                nameText[i].text = player.NickName;

                int playerScore = player.CustomProperties.ContainsKey("score") ? (int)player.CustomProperties["score"] : 0;
                scoreText[i].text = playerScore.ToString();

                i++;
            }
        }
        else
        {
            Debug.LogWarning("GET OUT");
        }
    }

    private void Update()
    {
        playerHolder.SetActive(Input.GetKey(KeyCode.Tab));
    }
}

I’m unfamiliar with the photon framework, but it looks as if you haven’t setup a custom property within the “Player” object that it provides. Is there a script somewhere that you are setting up these custom properties?

Here are a couple of links that might help