Newbie --default flash source file?

http://www.kirupa.com/developer/mx/listbox.htm

In the above example to create flash listbox, I did not understand this statement in the first step :

“Open the source file provided with Flash MX. You’ll see 4 layers : code, dynamic text, list box and background.”

Pls tell me whether there will be any default source page in flash or if the author referring his own created page??

Thx for any suggestions.

Rgds,
Sud