From the video: https://www.youtube.com/watch?v=N6dT0AKSvok

Create a new directory where the facebook api project is suppose to be. 

Create a new folder in the directory called vendor. 

Run CMD and navigate to the directory. 

To reverse to C:// type cd\ || To navigate forward, type cd

For example: cd xampp/htdocs/fbfile

Test run composer by typing composer. Once you see a whole list of commands, or that it doesn’t say the system does not recognize said command, all is good.

Back in the editor, create a composer.json. file. Key in the following in the file. { "require" : { "facebook/php-sdk-v4" : "4.0.*" } }

Save and return to the CMD.

Type composer install, then wait till everything is downloaded and installed.