From one Newbie to another, I can offer you what I’ve learned.
The basic (and this is very basic) breakdown of how a website is made is this:
1. Create a design in Photoshop or some other imaging software.
2. Export (this is where photoshop comes in handy) your design with “slices”. Photoshop even creates an HTML document for you.
3. Import your HTML file into a web creation application (such as Macromedia’s Dreamweaver), and edit it to your liking.
4. Upload your HTML, image, movie, etc files to your web server and you’re all set.
If you are trying to update a website, I would get your hands on Dreamweaver (or a similar program) and go from there. You can do quite a bit of “point and click” editing, and you don’t have to know how to code. This will probably make all the real web guys on here cringe, because from what I gather Dreamweaver creates really ugly code. However, from a simplistic standpoint, it will get the job done for you and hopefully make you look like you know what you’re doing 😉
There are also a lot of books out there on this specific software, as well as others.
Good luck!