Web Page SSO via okta and ACtive Directory

I am trying to setup an SSO login capability in our web application. I have a directory integration with Google in and running. I can’t seem to find the equivalent documentation to guide me through the same process to pass the login through to AD. I have the AD agent loaded and running and I have imported all the users (I hope this can be made automatic!) I don’t see where to add in the redirects - or what are the redirects - in the web.config (this is an IIS / asp.net application). Any help would be appreciated.

This sample app might be helpful:

The user will be redirected to the Okta login page to handle authentication.