oAuth2 Authentication in WordPress using WP OAuth Server and WP API plugins

You will have to follow the details from the developers website located here. (FYI, I am one lead on the project). Basically, what is boils down to, is that you are going to create a client in WP OAuth Server and give the details to your authenticated users. Your users would then setup using the grant type of “password” (user credentials). This is not ideal but will get you to a place your can expand the framework.

If you feel like getting your hands dirty, you can add a custom meta field to your user accounts that will say if they are allowed to access the data or not. Then, every time a user authenticates, you can either allow them access to WP OAuth Server or block access based on if their account has the correct meta value or not.