In your Main class, at the onEnable method, you'd do this

@Override
public void onEnable() {
    Bukkit.getServer().getPluginManager().registerEvents(new ListenerClass(), this);
}

Make sure your Main class implements Listener. Also, replace ListenerClass with the name of your listener class.

In your Listener class, you'd create the events exactly how you would do it if you only used one class. All your event classes will need to implement the Listener interface as well.