in some situation, 好=好的,this is applied in the situation when you agree with sth; only when sb ask about your apinion on sth then you have to give yoiur view which you think is good, fantastic,wonderful...(the degreed depends on your intonation, and voice volume)
Above the three words might equal to the words "yes, alright, okay, ok," , it is possible, foe we do not understand English very well as you do Chinese.
好吧, this phrase used in the situation that you have to compromise sth, kinda like you don't know yes or no, but accept it/ you don't mind it, or sometimes,
好了,means sth is done, it is used to describ the completed condition.
Hope that can help you.