Bill Tindall, E.Tn.
In the table feet there are to mortises that are "weaker" (for want of a better description) than the other two. The wide (or double) vertical post piece was attached to these mortises, bridging over the joint in the feet. The two narrow vertical pieces go in the "stronger" mortises. What I actually did is opposite of the orientation shown in the picture of the development model. I think how I arranged these pieces is the strongest of the possible orientations.