battery charger

Hi, everybody,I'm new to the RC world.I just got a Thunder AC6 charger from amazon, but I got confused, questions: how do you switch the "Man" mode to "Aut "mode for NiMH battery charge, and what are different between these two modes, does these two mode stop charging when the batteries is full? what else do I do to pay more attention to
thanks a lot..

(Man) means u have to tell the charger what u want it to charge or discharge (auto) means it will do what the battery needs