Installing SSL on Exchange 2013

Hello everyone and thanks for the help in advance.  I have been tasked with installing a SSL certificate on an Exchange Server 2013 for a small organization with no IT help.  I an neither an Exchange or SSL expert.  Previously, the organization was using self-signed certificates, but now wants to allow users to access OWA as well as Outlook clients.  I installed the GoDaddy SSL on the server successfully and it is recognized in IIS and on the Exchange Admin Console.  However, I am confused/terrified of the next step.  In reading documentation, it appears you assign services to the SSL through the Admin Console, but I have been fearful of taking the next step through lack of knowledge.  Currently, OWA can be accessed by going to https://mail.mydomain.com/owa.  I see no bindings on the default website pointing to mydomain.com and actually stops access when I add a binding.  So I stopped before I hurt myself.  Would someone be able to walk me through the steps?  Do I really only need to add the service to the SSL in the Exchange Admin for OWA to work on this SSL?  Any help would be appreciated.