Place the zipper on the seam and measure and mark the length of the opening.
Close the seam with machine stitching up to the mark. Press the seam open. Fold the seam allowance and press again.
Mark the left side of the opening with a fabric marker, about 1 cm away from the folded edge. Aline the right side fold of seam allowance next to the teeth of the zipper and tack in place.
Attach the zipper foot on the right side of the needle. Stitch about
3 mm from the zipper teeth, being careful not to catch the teeth in the needle.
Complete the other side by aligning the zipper teeth about 5 mm from the folded edge and tack in place.
Attach the zipper foot on the left side of the needle. Machine stitch about 1 cm from the folded edge.
Prepare and mark the seam opening as described in method 1.
Place the zipper face down on the right side of the seam allowance. Align the zipper teeth 3 mm over the folded edge of the seam allowance.
Pin and tack in place.
Attach the zipper foot on the right side of the needle. Stitch next to the teeth without catching the teeth in the needle.
The stitching is not visible on the right side opening, because the stitching is done within the seam allowance.
Complete the left side opening as described in method 1.