그래 can mean many things, but they can be grouped into three categories. 1. 그러해 (그러하다 in casual declarative ending) - (You're/It's) like that/so - indicates something is "in certain way". 2. 그러해 (extension of #1) - It/That/You is/are right. The perceived "certain way" agrees with what one expected. 3. 그렇게 해 (= 그러하게 해 - an imperative ending) - do it that way / as you like; Go ahead (as you wish). * The declarative forms can be turned into questions too: 그래? = Is that so?, Is that how it is?, etc. So, it can mean any of "You're like that", "It/That is so", "That's right", "Do so", or "Go ahead". (There are analogues 이래 / 이러해 / 이렇게 해 based on "this", and 저래 / 저러해 / 저렇게 해 based on "that") The translation you got looks all correct.