What file do I have to include in my php file

[eQX8HNMTU2]

What file do i have to include in my php file so I can start using the api.
Sorry if I seem ignorant but you have to explain better to people. The most important thing is to start using it before I can do anything with it.

require_once( ???

learn php

[izdrail]

You can use composer to autoload and then do require vendor/autoload.php