xtem is not a WYSIWYG (What You See Is What You Get) editor—in fact, it is not an editor at all. It uses Emacs (or the editor of your choice) to edit files. If you are interested in a WYSIWYG (or nearly WYSIWYG) interface to LaTeX and/or TeX, you might try LyX.

Start by reading the LyX home page at http://www.lehigh.edu/~dlj0/LyriX.html (LyX used to be called LyriX, until it was discovered that LyriX was already a trademark).