The documentation is here.
The AAD guide is here.
And the obligatory warning:
"Custom policies are designed primarily for identity pros who need to address complex scenarios. For most scenarios, we recommend that you use Azure Active Directory B2C built-in policies. Built-in policies are easier to set up for your configuration. You can use built-in and custom policies in the same Azure Active Directory B2C tenant. To learn more, see the overview of custom policies."
"Custom policy editing is not for everyone. The learning curve is demanding, the startup time is longer, and future changes to custom policies will require similar expertise to maintain. Built-in policies should be carefully considered first for your scenario before using custom policies."
I don't necessarily agree with this and am somewhat puzzled as to why they push this so hard.
The aim should be to encourage people to have a crack at it and learn something rather than scare them away.
I would spend some time reading through the getting started guide and get an overview of how the XML files work, how to upload them etc.
The big drawback about all of these guides is that they publish snippets of XML and it's always hard to figure out the context i.e. where they go in the document and how they relate to the other sections.
So I decided to publish all five files as gists (suitably redacted!).
I have three add-ons:
- Facebook - from the default policy
- ADFS - added but doesn't work because of the self-signed certificate
- AAD - which works
Also I did not have an actual application. I just tested using the "Run Now" button.
My B2C page looks like:
Also note that I added Application Insights which I strongly recommend for debugging (in SignUpOrSigninWithAAD.xml).