Hi; I have a newbie question please;

I have created a simple document that requires changes from time to
time....a word here and there....a sentence change...that kind of thing.
I have this document saved as a word document in "my documents".
What's puzzling me is this; when I open this document to make a change,
sometimes it just opens and allows me to make the change without
creating a "normal" document , then when I close it, closes normally
saving the changes I made. But sometimes I get an intercept when I close
the document telling me about a document called "normal" which has been
created, I assume as a function of word having to do with the changes or
editing I'm doing.

What I need to know is why I'm getting this "normal" document only part
of the time and not all the time if it's creation is required by word
when I'm editing this document. Also, I'm being asked something when
closing this "normal document" about changes being saved in it that I
don't quite understand .
Many thanks if someone can either bring me up to speed on this or point
me to a link where I can understand this better.
I'm fairly sure a link however, wouldn't answer the question about the
intermittent creation of this "normal" document, which is what's so
puzzling. If it did it every time, I could understand it better I think,
but it's apparently only being created under certain circumstances, and
I can't figure out what these circumstances are :-)
Thank you very much
Dudley