SSL certificate transfer to IIS

Hi It is my first post here so please accept my apologises if I asked in wrong place. So I my main domain is hosted on cpanel and my subdomain is hosted on on my onw server(IIS). I can see that inside of cpanel.net I got SSL certificates for my domain and my subdomain. I am not sure what do I need to do if I want to use these certificates on my server. Do I need to submit my "new certificate request" to cpanel? if yes, how then? Do I need to purchase something extra to get it work on my server?