If you have root previleges, you can simply find the correct (for your architecture) executable, move it to a directory in the users' PATH and give the name GraphEnt. Do not forget to make a symbolic link with the name graphent pointing to the same executable. If you do not have PGPLOT installed (obtainable from http://astro.caltech.edu/tjp/pgplot/), then the users should also define an environmental variable PGPLOT_DIR pointing to the directory that contains the two essential PGPLOT files that I also include ( grfont.dat and pgxwin_server).
If you want to install the program in your area, then go to the GraphEnt/bin/my_arch directory, uncompress a suitable executable, make a symbolic link with ln -s ./myexecutable ./graphent and add something analogous to the following three lines in your .cshrc file (assuming that you unpacked GraphEnt in your top directory) :
alias GraphEnt /usr/people/<username>/GraphEnt/bin/my_arch/<my_uncompressed_executable> alias graphent /usr/people/<username>/GraphEnt/bin/my_arch/graphent setenv PGPLOT_DIR /usr/people/<username>/GraphEnt/bin/my_arch