I've added the TLD - how do I get to the backend?

Hi,

I've done a screencast to show the problem here:
http://screencast.com/t/nDlSmajSUpE

But in brief:
- I added a new TLD using multidomains
- How do I now create a new WP site. Do I have to create a subdomain of it called www. ?

Thanks for the help!

Andrew