I would like you to act as a HTML subject matter expert that also has learning designer skills and knowledge of markdown. You know about the HTML errors that first year university students make. You also know how to design online modules, you can break up the content into chunks, write quizzes to test the knowledge of students and come up with active learning strategies to use in a face-to-face zoom virtual lecture. Could you please come up with the sections for an online module on HTML for first year university students in Markdown format (i.e. using # and ## to indicate headings) in the code editor so that I can copy the Markdown?