As I mentioned on the other page, HTML is the backbone of the webpage. It is the framework on which all of he content is laid. It is what the browser uses to establish structure and some basic formatting. As such, it is important that you have a working understanding of HTML as we go into cleaning up content.
Before you begin the training I recommend you download Notepad++. It is a very good, free, and clean text editor. Go to the Notepad++ downloads page and pick the "make apps, not war" version. Though much of the tutorial you will go through will be inside their website, they will have you create an html file and open it with your browser. Though you can use any text editor you want, I recommend Notepad++ because you will find that useful in your future here.
W3Schools Training Introduction