Help me please with word vba and its access database for update..!!!

Dear Experts,

Has anyone could help me please for this scenario:

I have a word document with its pop up form window...it contains of "Item Code", "Description", "Qty", "Unit Price" and "Total"...and it connected to a database access..my question is, what is the code if I fill out the quantity ("Qty") for order .i.e. I put "2"...then it will automatically reduce 2 qty in "Qty" field on the database access from Item Table...secondly, if the "qty" less than 1...it will show a message box as a warning...

Furthermore, I attach my file for your review and get understood about what I mean...

Please help me....

Thank you very much for your kind helps...

Jennifer :(