To order an SSL Cert simply visit https://www.blacknight.com/security/ssl/, select the cert you need and place an order.
If you bought an SSL certificate through our newer cp.blacknighthosting.com platform please see here for more information:
If your cert is to be installed on a VM package with Plesk or cPanel please see the following article:
Setting up SSL in Plesk
If you are renewing an SSL cert on our older cp.blacknight.com system then please see here:
Renewing SSL cert
If this is for a dedicated\colo server, server that isn't with us, or a VPS without Plesk then please follow whatever instructions you have for the Operating System or control panel you have running on your server.