Pin right side of neckline facing to right sides of bodice neckline. Match shoulder seams, and place center front at fold. Pin as needed.
For video on how to do this step (it can be a bit of a mind bender) wath Part I and Two of "Signature Box Top Neckline"
Stitch together at 1/4 Inch seam allowance.
Make sure interfacing is stitched into seam allowance.
Trim down bulk at corner.
Flip neckline and invert point.
Check to see if neckline points match in height. If they do not, stitch taller point with slightly larger seam allowance and check in with it again.