Archicad Addon

Hello. I want the development of a very basic addon in archicad via its api which you can download for free and has lot of examples. Development is in c++ and visual studio. I want a custom window in archicad , which will have a button a text and a listbox. The addon will be bound to a specific fill when the button is clicked, after that I want the text to show its Area property and the listbox to get filled with its individual coordinates X,Y of its nodes. I want this values to change automatically when the shape of the fill is changed.