Transferred Domain to point at site

Hi All,
I have set up a site with the default dreamhost subdomain, and finally been given the ok to transfer to old domain etc, to this site, but cant see how to do this.

I have transferred the domain into Dreamhost and can edit its DNS fine.

What I cannot seem to do, is point it at the wordpress instance that is on the dreamhost subdomain.

Any one know how to do this?