I'm trying to add authentication using Azure AD B2C to a web forms app. Unfortunately, every tutorial I've found is for MVC, except for this web forms tutorial. Using that tutorial, I've added this code to my startup.auth.cs:

public partial class Startup {

    // For more information on configuring authentication, please visit http://go.microsoft.com/fwlink/?LinkId=301883
    public void ConfigureAuth(IAppBuilder app)
    {
        app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType);

        app.UseCookieAuthentication(new CookieAuthenticationOptions());

        app.UseOpenIdConnectAuthentication(
            new OpenIdConnectAuthenticationOptions
            {
                ClientId = "my-client-id",
                Authority = "https://login.microsoftonline.com/my-tenant"
            });
    }
}

And that is working fine. However, I need to have sign up functionality as well as just sign-in, but I can't figure out how to do it, since everything I've found is for MVC, and I'm not sure how to convert that to what I need. I've tried adding code such as this:

app.UseOpenIdConnectAuthentication(CreateOptionsFromPolicy(_SignUpPolicyId));
app.UseOpenIdConnectAuthentication(CreateOptionsFromPolicy(_ProfilePolicyId));
app.UseOpenIdConnectAuthentication(CreateOptionsFromPolicy(_SignInPolicyId));

And that creates three more buttons on the login page, but clicking on them just gives a 404 error and no extra information, so I don't know how to make that work, either, or even if I'm headed in the right direction. I've never worked with B2C before, so if anyone has any suggestions/has done this sort of thing for web forms, I'd really appreciate some tips or sample code.