There are some commands in HTML that are confusing me. For example, what do the <nav> element and the <article> element do? There's a lot like this. <nav> <article> <section> <aside> <div> What are the purpose of these? I know what they do, what I'm confused about is why you'd want to use them. These elements create semantic sections, what I'm asking is, why is this needed? What does it change?
One important reason is accessibility of websites: If a screenreader (for blind people) knows (from recognizing these tags) which element contains the navigation (nav, which otherwise would just be a div), which elements are seperate, more or less independent blocks (articles and sections), it can guide the user much easier throught he structure of the page and help him/her to find the essential parts of the page quicker.
Another reason is that search engines can find the essential parts of a website, since the structure is much clearer.