Instant Text glossaries in MS word

I am planning to start using IT with MS Word. I was told that IT makes glossaries automatically for MS Word--(Had been using DocQscribe and for that platform--you needed to save the documents somewhere and then run the thing that compiles a glossary from single or multiple files--which I never did--). To make a new glossary for a new provider or surgery center...what do I have to do in MS Word 2007? Do I have to save each document individually--or is this where the "automatic" part comes in? I have gone over my IT manual and I did not see any specific instructions on how to do this...thanks for your help!