Focusing on your HTML question (and not how to actually get a website up, which requires renting server space, uploading your files, etc.) basic HTML is probably the easiest coding language out there to learn. There's a limited set of "tags" as EvilMonkey described, and most of the time, you just add the tag, put whatever you need to behind it, then close the tag by using the same tag name with a forward slash in front of it. There's a few that don't require a closing tag though, like the line break, and horizontal rule tags.

You CAN code up a page or even an entire website all from within good ol fashioned Notepad, but it'd be a slow, tedious, painstaking process, so most people use some sort of HTML editor, usually a WYSIWYG type of editor, the best out there is Adobe Dreamweaver, but it's expensive. There are many, many other alternatives just a google search away however. In those, most of the hard work is done for you, you just design the page like you would in say, Microsoft Word, and then it adds all of the tags and formatting for you. You can switch to a text version of the page for tweaking if you want. Once you have the page designed how you want, you just save it as a .htm or .html file and upload it to your server. Boom, you have a webpage!

You already have a basic idea of how it all works right here on GeekDrop. The editor that you're typing your posts into is an HTML WYSIWYG editor. When you click the buttons above, like inserting an image, or highlighting some text, clicking the link button, and adding a link, it's generating all of the HTML automatically for you . You can see the tags it created by clicking on the link below it named "Switch to plain text editor".

From there, as Evil Monkey started to point out, things can get much more technical and complicated, but also more powerful and better looking, by adding in other helper languages, that sort of 'intermingle' with the HTML itself. Languages like Flash, CSS, PHP, .NET, Cgi/Perl, Javascript, VBScript, Ruby on Rails, XML, and a very long list of others. They all have their own language that you need to learn in order to use them, some easy, some trickier. In order to be a hot item in the website coding world, you need to be a sort of Jack of all trades with all or many of them, (very few , if any are masters of all of them, it's just simply too much to learn and remember, and new languages popup constantly, and old languages change over time with upgrades, etc. Usually you just choose a specialty or two to focus on, and dabble in the others, asking for guidance as needed in forums dedicated to that language, to the people who chose to specialize in that language), but to simply make a very basic site for your own personal use, you just end up needing a basic grasp of HTML and Javascript (oftentimes).

I could go on and on, but entire books are written on the subject, and college semesters, so it's beyond the scope of just one post. You actually hit it right on the head with the title of your post, a GREAT place to start is to grab an HTML For Dummies book and start reading. Many of the languages I started on, I picked up a "For Dummies" book to kick start me. I love those Dummies books. If you have any specific questions in your ventures, ask away.