Generally speaking you need to tell your web server to handle stuff on port 443 (generally accepted as the Secure Port). Your Cert keys are going to have some information in them, but the web server will be using that information to manage serving of pages.
I installed an SSL about a year ago and followed the instructions on the Verisign web site. They were perfectly informative and things went exactly as the instructions said they would.
yes i have installed https using xampp program which installes apache2 on computer but i have no idea how to use openSSL functions of the php i woul be happy to hear about that