1. Open Unity and create a new project

2. Using Unity's package manager add Unity XR toolkit and Photon Pun2.

3. In your scene create a XR-UI to create the interface where the users can select the rooms.

• In the scene hierarchy panel (left) right click -> XR ->  UI Canvas (If you don't see the XR option, check your XR toolkit installation)

• The created canvas is larger than your scene. You have to rescale it to fit the scale of your scene. For example , in the width and height properties change it to 1.

• To add a background color to the canvas do right click on the canvas ->  UI -> Image  . Rescale the image to fit the canvas as we did in the previous step.

• Add 3 buttons to the canvas and rename them as room 1, room 2 and room 3

4.  Create an empty game object and rename it NetworkManager. Add a new script component to it and called it NetworkManager

5. Open the NetworkManager Script in your code editor and copy paste the following code.

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

using Photon.Pun;

using Photon.Realtime;

using TMPro;

public class NetworkManager : MonoBehaviourPunCallbacks

{

    private bool isConnected = false;

    public void ConnectedToServer()

    {

        if (!isConnected)

        {

            PhotonNetwork.ConnectUsingSettings(); // This code connects to the Photon server once the Unity scene starts

        }

    }

    public override void OnConnectedToMaster()

    {

        base.OnConnectedToMaster();

        isConnected = true;

    }

    public override void OnJoinedLobby()

    {

        // This callback happens when players joinig the general lobby

    }

    public void InitializeRoom(int room)

    {

        RoomOptions roomOptions = new RoomOptions();

        roomOptions.MaxPlayers = 4;

        roomOptions.IsVisible = true;

        roomOptions.IsOpen = true;

        string roomName = "CS1951t_"+room.ToString(); // The name of the room depends on the button label

        PhotonNetwork.JoinOrCreateRoom(roomName, roomOptions, TypedLobby.Default);

    }

    public override void OnJoinedRoom()

    {

        base.OnJoinedRoom();

        PhotonNetwork.LoadLevel(level_to_load); // Here you load you level

    }

    public override void OnPlayerEnteredRoom(Player newPlayer)

    {

        base.OnPlayerEnteredRoom(newPlayer);

    }

}

6.  Add the function InitializeRoom to the Onclick event of the UI Buttons