Click "Create Self-signed Certificate" in the "Actions" panel on the right side of the window. Enter a "friendly name" for the new server certificate in the appropriate box.

Windows Server How-To How To Create a Self-Signed Certificate Using the MakeCert utility of the Windows SDK will allow for you to issue your own self-signed certs. By Brien Posey 01/16/2015 ...

Moving an SSL certificate to a new server isn't always straight forward. Moving one from Godaddy to a new Windows Server proved down right frustrating.

Double-click "Server Certificates" in Features View, and then select "Create Certificate Request" from the Actions pane.