Reinforce facing with Vilene and then close darts. Fold piping strips in half lengthways and press. Afterwards sew the strips with raw edges to sleeve joining seams of front and back sections. Hem sleeves and insert sleeves with right sides facing. Neaten seam allowances, place in the front section and topstitch - this simultaneously finishes the lower armhole. Thenafter you have to close the centre-back seam between zip opening and hem slit. Stitch together the top edges of slit facing and insert the zip. Stitch facing right-sides together to the neckline. Snip slit end up to the last stitch. Then you have to turn facing inwards and topstitch. Close side seams and hem dress. Last but not least secure hem slit to the hem.