This is something you will need to take responsibility for after you have set up an account with Webcity. It is called re delegation and is usually easy and quick to do.
You will need to confirm who is currently holding your domain name. The company that is holding your domain name is your registrar. Your registrar should have a management page that will allow you to change the nameservers that are authorative for your domain name.
Remove any nameservers that are currently configured and add the following:
If Webcity is your registrar, you can use our management interface here: