You need to create a separate controller for that in your module at the following path:
/modules/supercheckout/controllers/front/fcont.php (where supercheckout is your module name)
and write the following code in the file:
class SupercheckoutFcontModuleFrontController extends ModuleFrontController
{
public function initContent()
{
parent::initContent();
$this->setTemplate('module:supercheckout/views/templates/front/order_detail.tpl');
}
}
You can use the following code to fetch URL of above controller:
$this->context->link->getModuleLink('supercheckout', 'fcont');