To learn html (= Hyper Text Markup Language; it's what www pages are written in), go to any page with your browser, view the source (on netscape/mozilla click the "view" button, then the "source" option). By comparing the source code with the page displayed on your browser you should be able to figure out how html works. The easiest way to set up a page is to copy the source of some page to a file (click "file" then "save page as") and edit it according to your taste. Or you can read this beginners guide.
You will need to set up a directory called "public_html" in your home directory, which should contain all your www pages (possibly in subdirectories); this is the default place that browsers will look for your www pages. Your home page should be called "index.html" and should be in the public_html directory. Usually a browser given a directory as an address will first look for a file called index.html in that directory, and display that file first if it exists. As an example of the relation between the www address and the unix address, this file has the www address "/~reb/courses/instructions.html", and its address in the unix file system is "~reb/public_html/courses/instructions.html". You can inspect my directory ~reb/public_html = /home/u1/fac/reb/public_html to see how to set things up.
You should assume that anyone in the world can read anything in the public_html directory: never put any confidential file in it, even if you do not have a www link to the file.
In unix/linux you also need to make all files of your www pages readable to everyone by
chmod a+r filename
and you need to make all directories containing these files (including public_html and your home directory) usable by
chmod a+x directoryname
The command pdftex can be used to convert tex files to pdf files (which can be displayed by most browsers).