If you're transferring your hosting account to us, you'll need to update your domain's DNS servers so that your domain will know to point to our web servers. Depending on which host you're coming from, there are different procedures to update your DNS servers for your domain. However, this can usually be done by logging in to your old host's client area and going to the domain management section.
Please contact technical support for the DNS server names and specifics on how to update them.
Alternately, you can have your domain completely transferred to our registrar, in which case we can update the DNS servers for you.