overview of files/directories for gnome desktop?

["Robert P. J. Day" <rpjday mindspring com>]

  i'm trying to throw together a short tutorial for new users on 
using the stock GNOME desktop that comes with RH 9 and, since i
typically have scripts to do most of what i want, i've rarely
used the standard icons so i have a couple simple questions
that lead into a more complicated question.

  starting with a brand new user account, and running "startx",
i notice that i have, initially, three icons in the top left
corner:

  user's Home
  Start Here
  Trash

but it's not immediately clear what these icons correspond to
in terms of actual apps.  unlike icons on the panel or in the
menus, right-clicking on these desktop icons and asking for
"Properties" doesn't specifically list what the icon represents.

  if i look in ~/.gnome-desktop, it's easy to see that there are
three files that correspond to those icons, but that still doesn't 
tell me everything about them.

  if i firther go into ~/.nautilus/metafiles, i can find several
more files that complete more of the picture.  but, for example,
if i double click on, say, Trash, where is the association from
that icon to the nautilus file maanger, which is invoked?

  i guess the more general question is, where i can read 
something which describes the general layout of the GNOME
file and directory hierarchy and how it all hangs together?
i've never had any problem customizing my own desktop by adding
extra launchers to the panel and so on, but in order to explain
how all of this works to new users, i should probably have
a much more detailed understanding of what's going on behind
the scenes.

  in particular, i'm curious about the "Start Here" icon.
the "getting started guide" describes it as a place "designed
to hold all of the tools and applications you need to access
when using your system."  technically, is this just a more
convenient way to access what's already available in the main
menus?  is there anything magical about that icon and what
it does that's not immediately obvious?  and so on.

  a pointer to the file and directory structure for GNOME
would work just fine, thanks.

rday