How to call PHPCap external package in laravel 5.5

I need to use the below package in Laravel 5.5 it's an external package.

https://github.com/iuredcap/phpcap

I download zip from above the GitHub URL and phpcap directory added in Laravel 5.5 vendor folder.

and use below code and in my controller.

use \IU\PHPCap\RedCapProject;

OR

use IU\PHPCap\RedCapProject;

and Call below function in my action

$project = new RedCapProject($apiUrl, $apiToken);

But every time given below error.

Class 'IU\PHPCap\RedCapProject' not found

via Chebli Mohamed