I need help mapping a domain manually

I’m trying to map a domain following this article, but I’m not sure if I’m doing it right:

https://catapultthemes.com/mapping-a-domain-on-wordpress-4-5-multisite

I don’t have a dedicated IP and I don’t want to use a plugin to map the domain. The new domain is pointing back to the old site and the new domain is currently hosted on SquareSpace but I have my DNS access to point as needed.

So my experience was:

1. My multisite domain was setup correctly by default.

2. I successfully switched nameservers of my new domain to my host nameservers. The DreamHost “website coming soon.” Page showed up as evidence.

3. I added the new domain as parked. The DreamHost “this is a parked domain” page showed up as evidence.

I4. In the Site Address (URL) field, I entered the full new URL to the domain name you’re mapping to.

5. I clicked Saved Changes and waited …. nothing happened. The domain is parked page stayed there. I waited 36 hours. Nothing. I don’t even know how to troubleshoot it.

I don’t know how to “point to the root of my multisite”.