Place false hem, fastenings facing down, centrally along bottom edge of cover with raw edges matching. Taking care to line poppers up with those on front cover, stitch along both sides of tape. Place front cover on a flat surface with right side facing and frill towards centre. Place back cover on top with wrong side facing. Matching raw edges, pin top and side seams.
Backstitch ends of fastening tape together across hems to neaten.
Turn right side out. Fasten thread securely. Repeat from other corner.