After importing Unity I get errors

I have never used photon before and not sure what to do...
I am importing pun into my project (card Game) it also has playmaker installed...

unity version is 5.3.4f1

those are errors ;

- Assets/Photon Unity Networking/Plugins/PhotonNetwork/PhotonNetwork.cs(3106,22): error CS0117: `SceneManager' does not contain a definition for `LoadScene'

-Assets/Photon Unity Networking/Plugins/PhotonNetwork/PhotonNetwork.cs(3132,22): error CS0117: `SceneManager' does not contain a definition for `LoadScene'

in Photon network script
this part comes back as error

 public static void LoadLevel(int levelNumber)
    {
        networkingPeer.SetLevelInPropsIfSynced(levelNumber);

        PhotonNetwork.isMessageQueueRunning = false;
        networkingPeer.loadingLevelAndPausedNetwork = true;
        SceneManager.LoadScene(levelNumber);
    }

and this;

 public static void LoadLevel(string levelName)
    {
        networkingPeer.SetLevelInPropsIfSynced(levelName);

        PhotonNetwork.isMessageQueueRunning = false;
        networkingPeer.loadingLevelAndPausedNetwork = true;
        SceneManager.LoadScene(levelName);
    }

what does that mean ? please help

thanks in advance

Beri