Charging lap top battery

My lap top is approx. 4/5 years old, it has two batteries, I tried charging the one that was in it when my daughter-in-law gave it to me, when I unpluged it from the ac after about 24 hours (she had not used this for a year or so) it would not come on after unplugging it from the ac, so I assumed it is a dead battery, the unit came with two batteries, my question is: do I just put the battery in leave it plugged into the ac and turn the machine off and the battery will charge (providing it is good) or is there some other procedure I must do to get it to charge, I haven't tried the second one yet, but wanted to know if there is a button I push or just shut it down with it plugged into ac, thank you