Dispatcher MVC multi controller

i have the following dispatcher but I want to have more than one controller, to split my code and have something more clean. How can I do that ?

<?php
$nameApp = "goater";

$action = "index";
if(key_exists("action", $_REQUEST))
$action =  $_REQUEST['action'];

require_once 'lib/core.php';
require_once $nameApp.'/controller/mainController.php';
session_start();

$context = context::getInstance();
$context->init($nameApp);
$context->title = "Index";

$view=$context->executeAction($action, $_REQUEST);

if($view===false)
{
    echo "Une grave erreur s'est produite, il est probable que l'action ".$action." n'existe pas...";
    die;
}
elseif($view!=context::NONE)
{
    $template_view=$nameApp."/view/".$action.$view.".php";
    include($nameApp."/layout/".$context->getLayout().".php");
}

?>

Thanks a lot