There are many different aspects of acting technique. One of them is building a character’s past. A helpful way to approach this is to know what the major events are in this person’s life. We ‘build’ these events by talking them out in improvised monologues so the character’s past is in us. If an event is referred to in the text, then you know you have to build it. But there are other events that are not mentioned in the text that we choose to build imaginatively, because it helps us get specific and fully own the character’s past, thus giving us confidence.