I need help on writing an article.

HTML stands for Hyper Text Markup Language. It's basically the easiest programming language to learn. Tags are the commands, telling the content what to do. For instance, < b > means bold text (without the spaces), so writing < b >bold< /b > turns into bold, < i >italic< /i > turns into italic, and < u >underline< /u > turns into underline. The slash means that is where the command ends.

As for spacing paragraphs, it depends on what the article is for. If it's a general article for the web, then you're probably safe having one blank line between each paragraph. The Internet has destroyed English written word, so there aren't really any clear, concise rules anymore. The old rules of format don't seem to apply to anything anymore.