Set up a PHP OAuth Provider

Alright I am trying to set up an OAuth Provider in PHP, but I just cannot get the hang of it. I've been referenced to this page a number of times, but I cannot wrap my head around it. Could someone help me out, step by step, or reference me to a more direct guide? Thank you very much.

What is OAuth PHP?

league/oauth2-server is a standards compliant implementation of an OAuth 2.0 authorization server written in PHP which makes working with OAuth 2.0 trivial. You can easily configure an OAuth 2.0 server to protect your API with access tokens, or allow clients to request new access tokens and refresh them.

Is OAuth and autho same?

OAuth 2.0 is a protocol that allows a user to grant limited access to their resources on one site, to another site, without having to expose their credentials. Auth0 is an organisation, who manages Universal Identity Platform for web, mobile and IoT can handle any of them — B2C, B2B, B2E, or a combination.

http://djpate.com/2011/01/13/how-to-write-a-complete-oauth-provider-in-php5 thast a pretty good tutorial to get a clue on the provider side