You can launch cssed from:
the command line with:
This will launch cssed and open a new document in cssed.
This will launch cssed and open the file foo from within cssed.
GNOME, by clicking on the cssed icon, providing that you have customized GNOME panel to add a launcher for cssed.
KDE, by clicking on the cssed icon, provided that you have customized the KDE menu to include cssed in, say, Development submenu, and added cssed to the applications launcher.
the Nautilus manager, by dragging and dropping a file onto cssed notebook editor, providing that you have at least version 2.2 of GNOME installed.
Emacs/XEmacs, providing you have installed the emacs launcher you will find on the cssed web site.