How to create a lobby for a telegram bot?

As part of studying TelegramAPI, I want to make a simple bot for playing Bulls and Cows.

The players are connected in the lobby and transferred to the class with the game. How to save lobbies and continue interacting with them?

Maybe I need to make an analogue of Room from the co.mafiagame project?

Bot.java

import com.fasterxml.jackson.databind.ObjectMapper;
import org.telegram.telegrambots.bots.TelegramLongPollingBot;
import org.telegram.telegrambots.meta.api.methods.send.SendMessage;
import org.telegram.telegrambots.meta.api.objects.Update;
import org.telegram.telegrambots.meta.exceptions.TelegramApiException;

import java.io.*;
import java.util.ArrayList;

public class Bot extends TelegramLongPollingBot {
    ArrayList<User> userList = new ArrayList<>();

    @Override
    public void onUpdateReceived(Update update) {
        long senderID = update.getMessage().getChatId();
        User senderUser = new User(0,"NULL");
        boolean isNewUser = true;
        for (int i = 0; i < userList.size(); i++)
            if (senderID == userList.get(i).userId) {
                isNewUser = false;
                senderUser = userList.get(i);
            }
        if (isNewUser == true) {
            userList.add(new User(update.getMessage().getChatId(), update.getMessage().getChat().getUserName()));
            // save();
            SendMessage(senderID, "You are a new player!");
            SendMessage(senderID, "/find");
            senderUser.state = 0;
        }
        if (update.getMessage().getText().toLowerCase().equals("/cancel") && senderUser.state == 1) {
            // cancel
            return;
        }
        if (update.getMessage().getText().toLowerCase().equals("/find") && isNewUser == false && senderUser.state == 0) {
            senderUser.isFinding = true;
            senderUser.state = 1;
            SendMessage(senderID,"Вы начали поиск...");
            int counter = 0;
            for (int i = 0; i < userList.size(); i++)
                if (userList.get(i).isFinding == true)
                    counter++;
            if (counter == 2) {
                User player1 = new User(), player2 = new User();
                boolean player1Finded = false;
                for (int i = 0; i < userList.size(); i++)
                    if (userList.get(i).isFinding == true )
                        if (player1Finded == false) {
                            player1 = userList.get(i);
                            player1Finded = true;
                        } else {
                            player2 = userList.get(i);
                            break;
                        }
                SendMessage(player1.userId,"Opponent finded: " + player2.userName);
                SendMessage(player2.userId,"Opponent finded: " + player1.userName);
                player1.isFinding = false;
                player1.state = 2;
                player2.isFinding = false;
                player2.state = 2;
                System.out.println(player1.isFinding + "" + player1.userId);
                System.out.println(player2.isFinding + "" + player2.userId);
        MyGame game = new MyGame();
        game.start(player1.userId, player2.userId);
            }
        }
        if (isNewUser == false && senderUser.state == 0)
            OldUserUpdate(senderUser,senderID,update);
    }
    public void OldUserUpdate(User user, long id, Update update){
        if(user.userId == update.getMessage().getChatId())
            SendMessage(id, "Unknown command! Use /help to see the list of all commands.");
    }

    public void SendMessage(long id, String mess ) {
        SendMessage sendMess = new SendMessage();
        sendMess.setChatId(id+"");
        sendMess.setText(mess);
        try {
            execute((sendMess));
        } catch (TelegramApiException e) {
            e.printStackTrace();
        }
    }
}