After setting up my project, and being able succefully use it through the provided public urls, I went on to follow the custom domain name instructions.

The instructions were to add a CNAME record to the domains DNS records. With host @, type CNAME, and value: <some provided railway url>.

When adding it to my squarespace domain dns records, the firs thing off was the a CNAME records cannot have the host set @ ('it gives you an error'). So I provided to add mydomain name instead of @.

I waiter for more then a weak, assuming the worst.

Then I started reading, and decided to try an ALIAS record, and that allowed the @ for the host, and the value that was given by railway.

Boom, with 1 minutes I could access the site via the customer domain. I couldn't enter because of HSTS. Quickly saw that railway is busy issuing the TLS cirt. That's where I'm at now, but the finish seems in in sight/close.

Just wanted to provide this info incase this a squarespace thing, or perhaps a mistake in the instructions.

By instructions I mean the instrucions in the setting tab on a service (github). In the networking section where the customer domain can be added. When you click on an already provided customer damain there are instruction to add a cname record.

Bye :)