Sew your pockets as per instructions or your preferred method.
Pin and sew the upper front crotch seams together from the notch near the base of the crotch and finish 6mm down from the V of the V neck.
With right sides facing, sew the front neck facing to the front neck with a 6mm seam. When arriving at the centre front keep the needle down and clip into the V of the facing to obtain a sharp point. Once clipped continue sewing along the other side of the neckline.
From the right side, understitch on the side of the facing close to the seam. Turn out and press.
Open out the neckline and facing and with right sides facing, sew one end of the open straps to the opened top edge of the front neck and front facing.
Turn back and fold the strap so that right sides are facing and stitch with a 6mm seam up from the armhole to the end of the strap.
Pull the facing out through to the right side and understitch on the side of the facing as far as you can get.
Repeat sewing the back crotch seams together and attaching back neck facing (steps 3, 4, 5 on your construction sheet).
With right sides together and with the strap sandwiched in between the upper back, stitch across from the neck to the armhole, keeping the needle down, turn the corner and stitch the back armhole and back armhole facing together.
Pull out the right side and understitch close to the seam on the side of the facing.
Cut the elastic and stitch it to the inside of the back waist area, start by sewing each end of the elastic in place first then sew along the top and the base of the elastic stretching it as you sew. Sew a vertical stitch through the centre back seam and the centre of the elastic.
With right sides facing sew the front and back side seams together, start sewing at the edge of the armhole facings, sew through the armhole seam and continue sewing down the side seam through the under pocket taking care not to catch the pocket opening as you sew (please note I have used a different method to attach my pockets in this example).
With right sides together sew the back and front in-leg seams together and complete sewing the front and back crotch seams.
With right sides together sew the side seams of the leg facings together, press the seams open and sew the base of the facings to the leg openings matching the notches as you sew. Understitch close to the seam on the side of the facing.
Pin the top edge of the leg facings to the leg of the pants, once in place stitch with a top stitch.
Hand stitch the armhole facings and neck facings to the main body using a blind stitch and press your fabulous new jumpsuit!