To move an instant messaging (IM) chat from the top to the bottom of a website, you'll need to access the website's source code and modify the CSS or JavaScript responsible for the chat's position. Identify the chat element in the HTML code, adjust the CSS properties like position and bottom to position it at the bottom of the page, and update the JavaScript code if necessary. After making these changes, save the file, test it in different browsers, and consider responsive design for various screen sizes. Back up the original code before making changes, and if you're unsure, seek help from a web developer.