Understanding the Generate Site Map Button and AI Prompt Engineering

hello! i'm just wondering how exactly "generate site map" button works so i can get better at sort of prompt engineering the ai. so when i make a description for the ai is it good practice to tell the ai what style i want the site to be in? or does describing the feeling i want the site to give work? is the ai just gpt 4o or is it a trained model? idk does anyone who made the button want to help me with prompt engineering