If your device is in a horizontal position, BlindSquare will announce directions correctly when its top edge is pointing in your traveling direction. The top edge is located opposite the edge with the lightening connector jack. If you carry your device in a vertical position, make sure its back points in your traveling direction.
As long as the screen is not locked, you may carry your device in portrait or landscape orientation.
When you lock the screen, you should carry it in portrait orientation.