Cut out lining for busk, side part and lacing of coutil fabric with seam allowance, sew to ribbon parts, fold seam allowance to coutil parts and topstitch. It is important not to cut back seam allowance, later on with sewing the tunnels the ribbons will be stabilised.
Fold upper and lower seam allowance of side and lacing parts to the inside and press.



Now cut again parts from coutil which will be faced with your Satin ribbon. Therefore cut side parts without seam allowance at all, lacing part without seam allowance on upper and lower edge, also at the edge for the ribbon part. At the busk part leave seam allowance just at the edge for the ribbon part.
My satin ribbon has a width of 7cm therefore I can cover my side part in one piece. If your ribbon is narrower sew two parts together. Pin exactly to the side part of the corset and topstitch. Leave one edge open (red arrow). Sew tunnels. I made 5 tunnels but only 3 bones will be inserted.


