If you still have any doubt you can post it here on the forum or can just contact our live chat support staff, they will assist you for updating nameservers for required domain.
You can update the nameservers you have received in the email by contacting your domain name registrar. It would be possible for you to update the nameservers of your domain name if your domain name registrar has given you the privileges to do so. If you do not have access to change your nameservers then you will have to contact your domain name registrar update the nameservers.