If you checked "register domain", your project page will be registered as mydomain.com (or .net, .eu)
Make sure the domain is available (use godaddy.com)
In order for us to customize the layout, you should provide all the necessary details (sample website, images, scripts etc.)
These will be handled after payment. If you want any customization to the core layout or code, choose this option.
Ftp will give you an empty folder you can manage to run your custom pages, images, videos etc.