For many of you, I imagine this post will be useless. For some of you though - I'm hoping it saves some time (it would have been nice to have someone save this time for me )
Anyway - this is pertaining to the purchase and installation of certificates - in this example it's an InstantSSL certificate from Comodo Security Services on behalf of AltaireSSL.
1. Setup a dedicated IP address
To do things properly, the domain that is using the certificate must be on a unique IP. Yes, you *can* set it up on a shared IP, but it's not a good idea, as you'll encounter big problems when you try to add your next secure site. Put it on a dedicate IP - save yourself the headache.
2. Deceide on the domain name
This step is important, and is often over looked. Ask yourself what address you want to use when accessing your secure certificate - would you rather they go to https://www.mydomain.com, https://domain.com or something like https://secure.domain.com or https://store.domain.com - be sure you know what you want before you continue. If you're using one of the latter two - setup the subdomain before continuing past this step.
3. Purchase the certificate
From WHM, near the bottom, under SSL/TLS - select "Purchase & Install SSL Certificate" - Go through the steps of filling out the details, and placing the order (this is a fairly linear, self-explanatory process, so I won't outline it). Be sure to use the domain name you selected in step 2. When defining the email address they should be using - use your own address (rather than your customer's/client's - it will simplify the process). Once you place the purchase you'll get an email indicating that you need to fax/email/mail some info to the certificate company - this is so they can confirm that you are who you say you are. Fax that information and wait for them to get back to you.
I've had this process take anywhere from 24 hours to 3 weeks. Yes it is annoying, but feel free to call up the company to see what's taking so long. Once they issue the certificate, you'll get an email with a zip file in it. Pay close attention to it - this is important to hold onto.
5. Install & Setup the Certificate
This is where most of the people I work with have difficulties - so be very careful. From WHM, under SSL/TLS select "Install an SSL Certificate and Setup the Domain" - if you have folowed my process as above, the .crt file and .key file will already be on the server. So, under domain - enter the domain name you selected in step 2, and used in step 3. Enter the username and the IP address you setup for that account (see step 1). Then click both Fetch buttons. The first Fetch button will grab the CRT file, the second will grab the KEY file. Note - although there is a sentence "Sorry.. cabundle not found, however you probably don't need one for this certificate ()." in the last field, we still need to setup the bundle file. This bundle file can be found in the email that the certificate company sent you.
In the zip file there is a file ComodoSecurityServicesCA.crt - open it in a text editor, copy the contents, and paste them into that last field in WHM. Then click the "Do it" button - and wait for the confirmation message.
So in a nutshell, I'm sure I'm duplicating information already avaialable on these forums - but perhaps someone will sticky this topic or start a sticky topic linking to tutorials and how to's
Best of luck,