can't open lilypond

[Candela]

Hi! I've just installed Lilypond, but it hasn't appeared in my menu, and
when I try to open it from terminal, this shows up:

GNU LilyPond 2.14.2
Usage: lilypond [OPTION]... FILE...

Typeset music and/or produce MIDI from FILE.

LilyPond produces beautiful music notation.
For more information, see http://lilypond.org

Options:
  -d, --define-default=SYM[=VAL]      set Scheme option SYM to VAL (default:
#t).
                                        Use -dhelp for help.
  -e, --evaluate=EXPR                 evaluate scheme code
  -f, --formats=FORMATs               dump FORMAT,...  Also as separate options:
      --pdf                           generate PDF (default)
      --png                           generate PNG
      --ps                            generate PostScript
  -h, --help                          show this help and exit
  -H, --header=FIELD                  dump header field FIELD to file
                                        named BASENAME.FIELD
  -I, --include=DIR                   add DIR to search path
  -i, --init=FILE                     use FILE as init file
  -j, --jail=USER, GROUP, JAIL, DIR   chroot to JAIL, become USER:GROUP
                                        and cd into DIR
  -o, --output=FILE                   write output to FILE (suffix will be
added)
      --relocate                      relocate using directory of lilypond
program
  -v, --version                       show version number and exit
  -V, --verbose                       be verbose
  -w, --warranty                      show warranty and copyright

Report bugs via
http://post.gmane.org/post.php?group=gmane.comp.gnu.lilypond.bugs


What should I do?
Thank you very much in advance!