I'm currently working on a CakePHP 3 application, trying to connect to Microsoft Azure using OAuth2. To this end, I'm trying to integrate the UseMuffin OAuth2 plugin. However, I'm struggling with the documentation. It seems to describe how to configure the plugin, but not how to actually use it. What methods do I call and how when I want to initiate an OAuth2 authentication? I'm somewhat familiar with OAuth2 itself, already wrote a little stand-alone PHP script that successfully authenticates using Curl. I'm just not sure how the UseMuffin plugin can help.

To be clear, the CakePHP 3 application I'm working on already has its own authentication scheme. I just want some users (not all) that are already authenticated with my application, to connect with Azure, so we can exchange information. I'm not sure the UseMuffin plugin can work alongside an existing means of authentication?