transfer new domain name to trial site?

I am new to squarespace - I'll start there 😀

I created a domain name that I'd like to transfer from the site that is active to a trial site that I love. The actie site was created using 7.1 and, unfortunately, without any template (the beauty of 7.1, perhaps, but not for me).  Any suggestions, welcome!  Thank you!

This guide should help: 

https://support.squarespace.com/hc/en-us/articles/205812098-Moving-a-Squarespace-domain-between-Squarespace-sites