Can anyone help me here?

I'm trying to follow this: Installing a StartSSL SSL Certificate with zmcertmgr - Zimbra :: Wiki

But I don't know what they're saying. Does anyone else think this?

What is this?
--3. Place server certificate in /tmp/ssl.crt.

Is this my private key I exported from Chrome to a file?
4. Place the private key in /opt/zimbra/ssl/zimbra/commercial/commercial.key

I've installed a gazillion certs on IIS from the pay services, and you usually just need the result file. I downloaded both of the files they mentioned and made the bundle but it's not working. Please advise. Thanks.

-Joe