Unity Networking API Public functions

so im lost on how to call the functions in the unity NetWorkLobbyManager i found this by peeking into the code

 using UnityEngine;
 using System.Collections;
 using UnityEngine.Networking;
 public class NetWorkLobbyManager : NetworkLobbyManager 
 { 
 public virtual void OnLobbyClientEnter() 
     { 
       Debug.Log("A player has joined the lobby");
     }
  }

but since it dosent do anything im pretty much lost on how to call the Networking OnSomething Functions any help is greatly apreciated