To create a home page using html, just create a directory called http in the top level of your home directory and make it world readable:
mkdir ~/http chmod a+r http
Now when you go to your homepage www.shadlen.org/~username you will see a directory of the files in this folder. If you create an html file called index.htm, this page will show up instead of the directory listing.
If you would like to create a personal wiki, please contact the sysadmin to give you the necessary files.