Some of the cheaper or newer SSL suppliers will require this to work properly (otherwise you may be prompted that the cert is invalid when it's not the case but it will certainly scare off your users!).
In the Apache vhost conf for the domain here is what you add:
Here is a full example of an SSL Vhost config in Apache using a CA Certificate file
Shortcut/Easiest Way To Create A Self-Signed Key:
openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key
Using the above, you instantly create a self-signed certificate valid for 1530 days and you can simply skip to step #5.) below.
If You Need a Real SSLCertificate (eg. Equifax/Openssl) then you need to create a CSR request (you'll need to follow Steps 1.) and 2.) in order to create the CSR. You then upload the CSR Certi........