Basically, that's the first time I'm playing with external identity providers in a federated authentication setup (Sitecore 9.1).

I can't say why but even after configuring everything I need following [this document][1] from Sitecore I still can't see an extra button on this page.

[![enter image description here][2]][2]


  [1]: https://doc.sitecore.com/developers/91/sitecore-experience-management/en/understanding-sitecore-authentication-behavior-changes.html
  [2]: https://i.sstatic.net/9vgON.png