Match up the bands’ seam lines to the shirt seam lines. Baste from top down, leaving the facing side of the bands free, as well as the entire band seam allowance at the bottom free.
Overlap to see if it matches up. Stitch.
Cut shirt down center front (if not already having done so) and clip at a diagonal at the corner. Press the finished seams toward the band. Press the facing SA to the inside. Topstitch. Make buttonholes on right front band. Turn the lower band SA to inside.
Adjust until it lays level. Press.
Carefully lift the bottom of the shirt while it’s still on the ironing board, making sure not to move the bands/shirt position.