I was asked where to find training in authority records. I can't find any online. The best is that offered by the Program for Cooperative Cataloging (PCC) as NACO or SACO training. If you have the chance, take it. SACO training is offered each year at ALA. NACO is offered at the OLAC annual conference. Training is also offered at other times and places. There is also lots of documentation available at the Web site.
Another issue is how to encode the information in the MARC format. The official documentation is the MARC 21 Concise Authority. I sometimes like to read another description and see some more examples. The Tag of the Month covers some of the more important fields.