How to Login as Active Directory User on Ignition?

[Transistor]

See also my recommendations in this post.

User Source vs Identity Provider with Active Directory

I recommend soft fallover mode to the default database and leave the Administrator account in there. That way you have a way in if the AD setup fails or you lock yourself out somehow (especially during configuration). You can also use the default user source to create and manage accounts for non-AD members such as contractors.