SSO integration with Azure cloud/office365

I’m trying to setup SSO with Azure/office365. I’m setting it up as a SAML 2.0 integration. I’m stuck at the x.509 certificate. It wants me to paste something in the box, but what I get from azure active directory is a downloadable security cert, not a text file. How do I get this certificate pasted in/uploaded in order to complete the SSO setup?