First, I would like to point out that the white fabric is the yoke of the dress which is sometimes mistaken for a collar. For this dress, I pipped the edge of the yoke and added eyelet trim. The embroidered bullion tulips can be found in the "Heirloom Embroidery Book."
This picture shows how the yoke buttons on the shoulders. I was unable to find buttons that I was happy with, so I made covered buttons.
And now for the pictures which are hopefully worth a thousand words. This picture shows the the front yoke pinned to the front of the garment, which would be Figure 16 in your pattern instructions. Any piping or trim would be applied to the yoke before this step. The same step is repeated for the back and back yoke.
With right sides together, the yokes and the yoke linings are stitched together as shown in Figure 17. An bottom edge of the yoke is left open, so that the yokes may be turned right side out after the seams are trimmed and clipped.
Once the yokes have been sewn on the garment is virtually done!