In PHP with FusionAuth, you can pass an initial parameter through the OAuth source and have it returned on successful login. While there may not be a specific example tailored to your exact use case, you can include your parameter in the OAuth request URL like "?parmOne=Mark," and FusionAuth should be able to return it to you upon a successful login.
FusionAuth provides a flexible system for handling OAuth parameters, and you can adapt the PHP example you mentioned to suit your needs. For a beginner-friendly example, you can start with the basic PHP integration and customize it to include your desired parameters.