Basic authentication with php cURL end point is Swagger

Hello every one,

I just joined in this community and this is my first post.  I have been assigned a task to communicate with Swagger test api with basic authentication. I am using PHP to communicate. I have been provided by username, password , client id and client secret. Here I have a doubt where to pass client id and secret ? Below is my code with username and password 

<?php

$username = 'user_name';
$password = 'pass_word';

$client_id = 'some_clinet_id';

$secret = 'client_secret';
$url = 'http://sometest.com/v1';
$ch = curl_init();
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));
curl_setopt($ch, CURLOPT_HEADER, 1);
curl_setopt($ch, CURLOPT_USERPWD, $username . ":" . $password);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
$return = curl_exec($ch);

Now I was in a confusing state where and how to pass these two variables 

$client_id = 'some_clinet_id';

$secret = 'client_secret';

Any help would be greatly appreciated.