Need help making a game

Hi, I’m a beginning Flash user. This is my first post but I’ve been lurking for a long time. I want to make a game where you have 2 pictures and one of them has different parts or hidden things that is different from the original. I need to know how to make a circle pop up when you click a certain part of the picture. Does anyone have any idea how to do this? Sorry if my explanation is a bit confusing. Thanks in advance!