Sew the back darts. Fold the center of the dart, match the dart lines, thread baste or pin baste and dart, and open if the material is thick.
Attach piece 2 to the pants front at the waistline. Fold piece 2 to the inner part and press the seam. Machine stitch on the outer piece.
Attach piece 2 to the pants front at the waistline. Fold piece 2 to the inner part and press the seam. Machine stitch on the outer side.
Pin the fly facing to the left side front piece (when you wear the trousers) with right sides together.
Stitch together from the top edge to the dot mark with a 1,5 cm (5/8″) seam allowance.
Open the fly facing. Trim and press the seam allowances toward the front.
Place the zipper face down (with the teeth toward the fabric) over the zipper facing, with the zipper ribbon touching the front seam. The zipper end should arrive just above the dot mark.
Stitch the left side of the zipper ribbon to the fly facing. Turn the facing in and press lightly.
Press the right side front piece (when you wear the trousers) 0,5 cm (1/4″) toward the inside.
Baste or pin the zipper to the folded edge.
Baste or pin the fly shield to the zipper.
Stitch very close to the folded edge through all layers (front, zipper and fly shield) from the top edge to the dot mark.
Close the zipper (but don’t cut it yet). Place the trousers front correctly and draw the topstitching line (you can use the front pattern piece or the fly facing as guide).
Stitch the fly topstitching throught both layers (front and fly facing).
Joining the side seams
With the right sides of both the front and back pants facing together, match the edges of the back pants with the seam line of the side edges of the back pants. Match the construction marks of the seats, thighs, knees, and bottoms of the front and back pants. Pin and baste.
Stitch together the front and back pants 1/4" from the sides of the front pants. Double stitch from waist down to knee.
Joining Inseams of the Pants
Match the crotches together in front and back . Stitch the crotches together from the back of waistline up to the placket snip. Double stitch the joint to reinforce
Attaching the waistband
Join the right sides of the waistband and the pants together at the waist. Extend the waistband 1/2" from the left and right plackets .
Spread open the left fly and stitch together at the waistline
Turn the waistband rightside out. You need to pull out the corners with a sharp tool or something so that they look sharp.
Turn the waistband facing the wrong side and fold the edges then pin (make sure it is clean)
Sew the and top stitch folded edge
Fold and pin the edge of the bottom part
Finally, Sew it neatly