which side of the the power adapter should you connect first? A is for the end to your Macbook(pro or other portable ones), B is for the other end to an electrical outlet. Before you turn on your MacBook, first you should connect A or B and what about turning off your MacBook? and why would that be? does it do sort of harm to the Macbook when you do not do it appropriately. this may be quite a simple question, but i really have no idea theoretically. Can anyone educate me please.