If you already have your SSL Certificate and just need to install it, see
Zeus SSL Certificate Installation.
How to generate a CSR in Zeus Webserver
Log in to the web server.
Select SSL Certificates.
Click on the Create button to create a new certificate set.
Choose 'Buy a Certificate From Another Certifying Authority'. Click on OK.
Fill in the appropriate fields with your DN information.
Click OK.
Copy and paste the CSR (including the BEGIN and END tags) into the DigiCert Order form.
After you receive your SSL Certificate from DigiCert, you can install it.