Most Hosts will provide you with at least a shared certificate and help you with it.

On my host, is was just a manner of logging on to the admin panel for my host, and noting what the SSL URLs were.

And yes, you'll have to use the Authorize.net module in ZenCart Admin as Sermon pointed out,

Good Luck and feel free to ask more questions,.

Quote Originally Posted by Sermonzone
Your host should help you with the SSL setup. This is where Zen Certified Hosting is really handy.

I use Auth net and don't remember having to tell them anything about the SSL. You will have to go through the setup in Zen Cart admin, on the Auth.net website and I think I even had to call to confirm some stuff. A little tedious but mine has given ZERO problems since setup 6 months ago.