How to add a name to the Thank you for the order page in Opencart 3?

Question

opencart

I want to add a name to the Thank you for the order page, I write the variable {{ firstname }} to the tpl, it does not enter, I understand that I need to go to the controller, I even output an array
if (isset($this->session->data['order_id) '])) {
// $this->load->model('checkout/order');
//
// if($orderData = $this->model_checkout_order->getOrder($this->session->data['order_id'])){
// echo '';print_r($orderData);echo '';
// }
// }
and the name under this key, but still does not display

Answer 1

you must have a $data['firstname'] variable in your controller, if it exists, then everything will be displayed