This is how it works.
Inside Box and One - 4 players stand near the painted area/free-throw area, and the best defender among the PG/SG/SF, locks down the best perimeter shooter of the opposing team. Best use against Look Inside/Low Post. Teams that rely heavily on their Cutters/Slashers (Driving), Post up players (Inside Shot), and Jump shooters (Jump Shot).
Outside Box and One - 4 players stand near arc/3pt. line, and the better defender between PF and C will protect the shaded area. Best use against Motion/Run and Gun. Teams that rely heavily on their outside shooters with PF as a stretch 4.