The vertical arrows correspond to the Up/Down physical setting of the arrows on the panel backside. The LED Panel Layout orientation is as if viewed from the front of the panels. 'O-1', 'O-2', 'O-3', etc are the outputs ports on the Octoscroller. 'P-1', 'P-2', 'P-3', etc. is the panel order for each output. The first panel connected to the Octoscroller output is 'P-1', the second panel is 'P-2' and so forth.