Step 1: Pin & Sew the Crotch Seam
Step 2: Press Back Half Right Side Seam Allowance.
Step 3: Pin & Tack Zip on Right Side.
Step 4: Prepare the Left Fly Facing...
Step 5: Sew on the Left Fly Facing
Step 6: Pin Left Fly Facing Back
Step 7: Prepare the Zip Shield
Step 8: Pin, Tack & Sew Right Side
Sew close to the zip at the front.
(In this picture I have already tacked the left side of my zip to the left fly facing)
Step 9: Pin Left Side of Zip to Left Fly Facing...
Pin the zip shield out of the way & sew the left side.