• By Default Now User will be able to  Access Admin Panel of Authorization You have to grand Permission yourself
• Add Following Code 

Path: Project_name\vendor\yiisoft\yii2\web\Controller.php 

Public function beforeAction($action)
{
if(!Yii::$app->getModule('admin')->Authorization()){
echo"<h1>YouDonotHavePermissiontoaccess".$action->uniqueId."</h1>";
exit;
}

if(parent::beforeAction($action)){
if($this->enableCsrfValidation&&Yii::$app->getErrorHandler()->exception===null&&!Yii::$app->getRequest()->validateCsrfToken()){
thrownewBadRequestHttpException(Yii::t('yii','Unabletoverifyyourdatasubmission.'));
}

returntrue;
}

returnfalse;
}

• You will have to add link on your Menu