Subdomain and cloudflare

The following scenario I have planned; is our primary domain (for Dutch computer science education content). It’s DNS traffic is handled by Cloudflare because of its excellent DDoS support.
I want to use for the development of a teaching portal. When everything is working, I want to move that to the main domain and use for what is now the main content.

How do I point to
When all the development is done, I want to point to Can I just switch the domains when it’s all working?

I’ve setup the following in Cloudflare; I pointed dev. to Is this the correct load balancer?

(note, bjoc is a translation of the beauty and joy of computing. A great resource to learn to code!)

You will need to define the custom domain first before you can add the CNAME record on DNS Zone.

So make sure the domain is added to your custom domain list : Custom domains | Netlify Docs

I’ve added that some time ago,

Hi @moorlag , is our legacy load balancer. The current one is

How do I point to

You’ll want to assign the hostname to the Netlify site after configuring DNS.

Hope that helps!