Don't follow their instruction coz it has an error  or something is
missing. Just open a notepad, paste the content of applet.htm which I
created for you (see below). Then save the file  as applet.htm not
applet.txt (be sure you choose 'all files' for file type  in notepad)
and be sure you save it in the same location of your class  file
(let's say you save your class file at c:\, then you should save the
applet.htm to c:\ also)

Double click the applet.htm in your file explorer in which your
current web browser ( IE or Netscape) will open and it will display
and run  your applet  application.