Signed certificates for transport SSL

Hey everyone.

I'm trying to understand how I go from once my CSR is sign by a CA to using it for remote clustering via transport SSL settings. I've gotten my certificate signed and received a .cer file. I'm a little confused as to how to use this in combination with my already created ca.p12. There seems to be no documentation for when the certificate is signed? I'd be happy to provide any clarifications if needed.