To start Emacs type
xemacs & in your xterm.
Although Emacs is traditionally a keyboard based editor, it nowadays comes with a menubar at the top, which allows you to do the most imporant things using a mouse.
Everything that you will need for this course can be found under the menu item File.
If you want to learn a bit more about Emacs have a look at this site (or use google to search for other introductions to Emacs - there are loads on the web).