I created a Web Forms application a LOOONG time ago. There's no start up folder, startup.cs, startup anything. There's a default page that redirects to the original login page I created. That's what I have NOW.
What I want is to do away with the custom login page in favor of using Azure AD. Everything that I have found to do this mentions a startup file and folder that I do not have.
Question: Is there a way to use AD in the OLD web form applications (literally no startup file, I can create one but I'm sure there's more to this than just naming a file "startup") or is my only option to upgrade my entire project?