Access 2007 - Design of main form to sub form linkage

My OS is win 7 prof 64 bit and I use office 2007.  I am trying to create a simple book distribution database for my non-profit org and am stuck on the relationship linkages.  I attach herewith a Word 2007 document on the design that I have so far and also the Access 2007 file that I created to begin the project.   My present problem is the set up of the main form and the imbedded sub form.  Hope the experts can please take a look and let me know what I am doing wrong or how to correct it, and it will be wonderful if I can have the corrected access file.   once I get the initial glitches over and done with, then I can move on slowly but surely implementing one item at a time. Thank u.
Book-Distribution.accdb
Design-of-a-book-distribution-da.docx