The hierarchy editor tells Poser the relationship between the different parts of a figure, and shows what is parented to what. Also can show parameters, cameras, lights. You can use it to quickly make parts visible and invisible. (I assume you already found it is located in the Windows menu.) Might be helpful if you were more specific in your question. What is it that you're trying to do with the hierarchy editor? Lots of people here to help you but the answers are different depending on the question.