How to use SSL certificates in OSX Server

I have setup OSX server with a host name that is pointed properly to my OSX server. My question is about using certificates that were purchased through my domain registrar.

I bought a cert and after the validation process, I was given a link to download 4 certificate files.

AddTrustExternalCARoot.crt

DV_NetworkSolutionsDVServerCA2.crt

DV_USERTrustRSACertificationAuthority.crt

[domain name].crt

So after downloading these and opening them one by one, I installed them in the keychain as a system cert.

The part I cant figure out is how to use the domain cert instead of the one that the server creates upon completion of setup (the self signed one).

On the certificate selection in the sidebar, I can choose Import a certificate identity, but when I drag my domain cert into the box, it shows up as a non-identity cert and the Import button is still grayed out. I dragged all four certs there and all of them show as non-identity certs.

If I go down the path of the Get a Trusted Certificate, it takes me through the CSR request which I dont think I need since i have my certificates already.

Am I missing a step? Or do I need to export from the keychain, then import into the server application? Seems like the new certificates should show up in the server application. Any help would be greatly appreciated.