use php library without composer

Any1 got a idea how to use this library since i cant use composer?

https://github.com/unsplash/unsplash-php

since i never worked with composer before i dont now how to use this library

Crew\Unsplash\HttpClient::init([
   'applicationId'  => 'YOUR APPLICATION ID',
   'secret'     => 'YOUR APPLICATION SECRET',
   'callbackUrl'    => 'https://your-application.com/oauth/callback',
   'utmSource' => 'NAME OF YOUR APPLICATION'
]);


$search = 'forest';
$page = 3;
$per_page = 15;
$orientation = 'landscape';

Crew\Unsplash\Search::photos($search, $page, $per_page, $orientation);