Step 5: Basic Construction
Sew the front panel to the back panel (right sides together) starting at the hips and ending just after it becomes maximally wide for the bust.
Measure the top flaps where your neckline will go. Use that measurement to divide your top flaps into thirds.
Sew* the outside thirds, leaving the middle third open as a hole for your head.
*Sew these at 1/2 your normal seam allowance.
Fold in half lengthwise, right sides together.
Sew, leaving 3" unsewn at the end.