Instances without new keyword

Hi, I have script named Core. In others scrips I wroted this

 public Core core;

    public className(Core MainCore) {
        core = MainCore;
    }

in Core:

using UnityEngine;
using System.Collections;

public class Core : MonoBehaviour {

    private MySQL mysql;
    private NetworkManager networkManager;
    private Login login;
    private FirstPlay firstplay;
    private Hud hud;
    private Loading loading;
    private Typ typ;
    private PlayerManager playermanager;

	void Start () {
        mysql = new MySQL(this);
        networkManager = new NetworkManager(this);
        login = new Login(this);
        firstplay = new FirstPlay(this);
        hud = new Hud(this);
        loading = new Loading(this);
        playermanager = new PlayerManager(this);
	}

    public MySQL getMySQL() { return mysql; }

    public NetworkManager getNetworkManager() { return networkManager; }

    public Login getLogin() { return login; }

    public FirstPlay getFirstPlay() { return firstplay; }

    public Hud getHud() { return hud; }

    public Loading getLoading() { return loading; }

    public PlayerManager getPlayerManager() { return playermanager; }

}

How I can make instance without this errors ? PS: I can’t use static.

You are trying to create a
MonoBehaviour using the ‘new’ keyword.
This is not allowed. MonoBehaviours
can only be added using
AddComponent(). Alternatively, your
script can inherit from
ScriptableObject or no base class at
all UnityEngine.MonoBehaviour:.ctor()

You have not said what ‘this errors’ are, but I’m guessing you are trying to do something like

Core c = new Core();

If so, you can’t do that with MonoBehavior-derived classes. Use Instantiate instead.