[I WISH TO SAVE ONE AUTOMATIC BACKUP COPY]

I want please to be able to save a word document automatically, as a back up
for a book I am working on.

So for example, when I save this book, I would like for it please to be
automatically saved in a safe location, somewhere else, without me saving it
twice I mean, but automatically as a backup copy?

PS: I know I have repeated myself there but I just want to make it clear
what I am trying to do, as people in the past have been confused.