In the video under Publish Settings, the Training video has "Change GroovePages Subdomain" in that box, but mine has "Set GroovePages Subdomain"; and it won't let me select Host or Publish; If I click on the "Set your Groove Pages subdomain", it gives me a warning: "Warning: changing will move...
If this is the first page you've published, then you can put anything into that subdomain (i.e. affiliate, SAS, or any word can be your subdomain). Type something into there when it pops up, then save it. And it should you proceed to the next step