The "Anchor" page is the anonymous authentication provider that is used by Juno - i.e. https://internetcomputer.org/internet-identity

So you would need to create an "Anchor" there to be able to sign-in. I plan to add additional auth provider in the future but currently, it's the one.

Once and if you create an auth there, you can drop me a PM on https://twitter.com/daviddalbusco afterwards

Happy to provide you an invitation code!