Can someone give me a quick rundown on how Certificates run within a domain. I know it sounds daft, but I can't get my head round it (maybe it's a Friday think).

Basically, we are setting up a test RDP system for some bits and bobs and I need to install a certificate for the servers to use and I can't for the life of me figure out how to do it! I have enabled the CA role on the DC which seems happy enough, but what do I do then to issue the certificate so I can install it on the RDP servers?