You can get to that overview screen by going from the main screen, clicking 'learn about new process', then 'next how to pre-register' and there is an 'overview' link. When I clicked 'add auction' I then got the user id stuff. Added a new user id and registered when I got the email (went to my spam).
Once I did that, I had to go back to the overview screen, click 'add auction' and then requested I setup a profile with my name, address, etc.
After that, I could then add an item to the store (which I did)
I hope this is cleaned up because it is massively confusing. For example 'register your items' kicks it to the 2019 page.