Adding random items to a list

Am trying to code a blackjack game as my first project in C# and this is my first attempt and I've been getting this error :

Assets\NewBehaviourScript.cs(17,9): error CS0103: The name 'playerdeck' does not exist in the current context

Assets\NewBehaviourScript.cs(17,24): error CS0103: The name 'random' does not exist in the current context

This is my code

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class NewBehaviourScript : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        char[] Deck={'A','2','3','4','5','6','7','8','9','J','Q','K'};
        List<char> playerdeck = new List<char>();
    }

    // Update is called once per frame
    void Update()
    {
        playerdeck.Add(random.next(0, Deck.length));
        playerdeck.Add(random.next(0, Deck.length));
        System.Console.Write(playerdeck[0]);
        System.Console.Write(playerdeck[1]);

    }
}