var $logged_in = false;
var $referrer, $url;
public $userinfo = array();
        

            $this->logged_in = $this->checkLogin();

            if (isset($_SESSION['url'])) {
                $this->referrer = $_SESSION['url'];
            } else {
                $this->referrer = "/";
            }
            $this->url = $_SESSION['url'] = $_SERVER['PHP_SELF'];

            $this->SurfControl();

private function checkLogin() {
            global $db;
            if (isset($_SESSION['USER']['ID']) && isset($_SESSION['USER']['SID'])) {
                if (!$db->checkActiveSession($_SESSION['USER']['ID'], $_SESSION['USER']['SID'])) {
                    $this->Logout();
                    return false;
                } else {
                    $db->addActiveUser($_SESSION['USER']['ID'], $this->time);
                    $db->updateUserField($_SESSION['USER']['ID'], "timestamp", $this->time, 0);
                    return true;
                }
            } else {
                return false;
            }
        }

        public function login($uid) {
            global $db, $generator;
            $this->logged_in = true;

            $_SESSION['USER']['SID'] = $generator->generateRandID();
            $_SESSION['USER']['ID'] = $uid;

            $db->addActiveUser($_SESSION['USER']['ID'], $this->time);
        }

        public function Logout() {
            global $db;
            $this->logged_in = false;
            $db->updateUserField($_SESSION['username'], "sessid", "", 0);
            if (ini_get("session.use_cookies")) {
                $params = session_get_cookie_params();
                setcookie(session_name(), '', time() - 42000, $params["path"], $params["domain"], $params["secure"], $params["httponly"]);
            }
            session_destroy();
            session_start();
        }

        private function SurfControl() {

            $pagearray_guest = array("def", "register", "login"); // Разрешенные модули для гостя (не авторизованного пользователя)
            $pagearray_user = array("def", "game", "user", "settings"); // Модули для зарегистрированного пользователя

            $app = empty($_GET['app']) ? 'def' : $_GET['app'];
            $app = rtrim($app, '/');
            $app = explode('/', $app);

            preg_match("/([a-zA-Z]*)([0-9]*)/", $app[0], $url_step);

            if (!$this->logged_in) {
                if (!in_array($app[0], $pagearray_guest)) {
                    header("Location: " . DOMAIN . "");
                }
            } else {
                    
                    if (!in_array($app[0], $pagearray_user)) {
                        header("Location: " . DOMAIN . "");
                    }
                    
            }
        }

     function checkactiveSession($id, $sessid) {
            $user = $this->getUserArray($id, 1);
            $sessidarray = explode("+", $_SESSION['USER']['SID']);
            if (in_array($sessid, $sessidarray)) {
                return true;
            } else {
                return false;
            }
        }

        function getUserArray($ref, $mode) {
            if (!$mode) {
                $q = "SELECT * FROM ".TIGA_BD_PREF."users where login = '$ref'";
            } else {
                $q = "SELECT * FROM ".TIGA_BD_PREF."users where id = $ref";
            }
            $result = mysql_query($q, $this->connection);
            return mysql_fetch_array($result);
        }

        function updateUserField($ref, $field, $value, $mode) {
            if (!$mode) {
                $q = "UPDATE ".TIGA_BD_PREF."users set $field = '$value' where login = '$ref'";
            } elseif ($mode == 1) {
                $q = "UPDATE ".TIGA_BD_PREF."users set $field = '$value' where id = '$ref'";
            } elseif ($mode == 2) {
                $q = "UPDATE ".TIGA_BD_PREF."users set $field = $field + '$value' where id = '$ref'";
            }
            return mysql_query($q, $this->connection);
        }

        function addActiveUser($id, $time) {
            $uip = $_SERVER['REMOTE_ADDR'];
            $q = "INSERT into ".TIGA_BD_PREF."active values ('$id',$time,'$uip')";
            if (mysql_query($q, $this->connection)) {
                return true;
            } else {
                return false;
            }
        }
            
        function UpdateOnline($mode, $name = "") {
            global $session;
            if ($mode == "login") {
                $q = "INSERT IGNORE INTO ".TIGA_BD_PREF."online (name, time) VALUES ('$name', " . time() . ")";
                return mysql_query($q, $this->connection);
            } else {
                $q = "DELETE FROM ".TIGA_BD_PREF."online WHERE name ='" . $session->username . "'";
                return mysql_query($q, $this->connection);
            }
        }

<?php

/*
      +--------------------------------------------------------------------------
      |  TigaEngine
      |  ========================================
      |  By Tiga Team
      |
      |  ========================================
      |  login.php - модуль авторизации
     */

if (!defined('TIGA_RUN')) {
        die($lang_core['access_deniend']);
}

Далее нам надо проверить передана ли нам форма , после } Добавим код

if($_POST['send_login']){
        // Логика
}else{
        // Шаблон
}

<form method='post'>
        Логин:<BR>
        <input type="text" name="login" value=""><BR>
        Пароль:<BR>
        <input type="password" name="password" value=""><BR>
        <input type="submit" name="send_login" value="Отправить">
</form>

$content = $tpl->parse('login.tpl');

$password = strip_tags(addslashes($_POST['password']));
$login = strip_tags(addslashes($_POST['login']));

if (!$email && !$password) {
     $_SESSION['ERROR']['1'] = 'Поле логина и пароля являются обязательными для заполнения.';
}

$q1 = "SELECT * FROM ".TIGA_BD_PREF."users WHERE login='" . $login . "' AND password='" . md5($password) . "'";
$array1 = $database->query_return($q1);

if (count($array1) == 0) {
     $_SESSION['ERROR']['2'] = 'Ошибка логин/пароля.';
}

if ($_SESSION['ERROR']) {
     echo '<h2>Ошибка Авторизации</h2>';
     if ($_SESSION['ERROR']['1']) {
      echo '<p>' . $_SESSION['ERROR']['1'] . '</p>';
     }else{
      echo '<p>' . $_SESSION['ERROR']['2'] . '</p>';
     }
     session_destroy();
}else{
     foreach ($array1 as $row) {
      $u_id = $row['id'];
     }
         
     echo '<h2>Успешная Авторизация</h2>';
     echo '<a href='.DOMAIN.'>На главную</a>';
     $session->login($u_id);
         
}

<?php

/*
      +--------------------------------------------------------------------------
      |  TigaEngine
      |  ========================================
      |  By Tiga Team
      |
      |  ========================================
      |  register.php - модуль регистрации
     */

if (!defined('TIGA_RUN')) {
        die($lang_core['access_deniend']);
}

if($_POST['send_register']){
        // Логика
}else{
        // Шаблон
}

<form method='post'>
        Логин:<BR>
        <input type="text" name="login" value=""><BR>
     Email:<BR>
        <input type="text" name="email" value=""><BR>
        Пароль:<BR>
        <input type="password" name="password" value=""><BR>
        <input type="submit" name="send_register" value="Отправить">
</form>

$content = $tpl->parse('register.tpl');

$password = strip_tags(addslashes($_POST['password']));
$login = strip_tags(addslashes($_POST['login']));
$email = strip_tags(addslashes($_POST['email']));

if (!$email && !$password && !$email) {
     $_SESSION['ERROR']['2'] = 'Все поля обязательны для заполнения.';
}

if (!eregi("^([a-z0-9]+)([._-]([a-z0-9]+))*[@]([a-z0-9]+)([._-]([a-z0-9]+))*[.]([a-z0-9]){2}([a-z0-9])?$", $email)) {
     $_SESSION['ERROR']['3'] = 'Неверный формат EMAILa.';
}

if (strlen($password) < 6 || strlen($password) > 12) {
     $_SESSION['ERROR']['4'] = 'Пароль должен состоять от 6 до 12 символов.';
}

$q1 = "SELECT * FROM ".TIGA_BD_PREF."users WHERE email='" . $email . "' AND login='".$login."'";
$array1 = $database->query_return($q1);

if (count($array1) != 0) {
     $_SESSION['ERROR']['1'] = 'Ошибка, логин или email уже используется';
}

if ($_SESSION['ERROR']) {
     if ($_SESSION['ERROR']['2']) {
      echo '<p>' . $_SESSION['ERROR']['2'] . '</p>';
     }else{
      if($_SESSION['ERROR']['1']){
       echo '<p>' . $_SESSION['ERROR']['1'] . '</p>';
      }else{
       echo '<p>' . $_SESSION['ERROR']['3'] . '</p>';
       echo '<p>' . $_SESSION['ERROR']['4'] . '</p>';
      }
     }
}else{
     $password = md5($_POST['password']);
        $q2 = "INSERT INTO users (login , email, password) values ('" . $login . "','" . $email . "','" . $password . "')";
        $res = $database->query($q2) or die(mysql_error());
     echo 'Регистрация завершина! <a href="'.DOMAIN.'">на главную :)</a>';
     // Тут продолжим регистрацию в след уроках  
}