Can someone tell me more about the plumbing of Azure listeners

I've done this: https://docs.microsoft.com/en-us/dynamics365/customer-engagement/developer/walkthrough-configure-azure-sas-integration and registered a create custom entity step against it.  (the invisible out-of-the-box plugin)

Now, assuming I can write an Azure listener, it seems there needs to be more than just the program.  All that information that I entered to register the Azure Service Bus endpoint needs to be known to the listener so that it knows where to listen.  The CRM documentation falls short of walking one through to the end of deploying the listener.

Anyone's guidance would be greatly appreciated.