SAML Config for AEM Author

We are running AEM  6.5.16.0 on-premise and we are attempting to utilize the SAML 2.0 Auth Handler.
I've gone through the steps in this article a few times, but cannot get a request to hit the handler and redirect to the IDP.
Any request made to the AEM Author VM goes to the local granite authentication login screen.

I figured that I'm missing something blatantly obvious. Any thoughts or tips?

PS I have inherited our AEM environment and have not had any AEM training yet. Learning the fun way. #YOLO

https://experienceleague.adobe.com/docs/experience-manager-65/administering/security/saml-2-0-authenticationhandler.html