Right now there's no Debian package available. Please get the sources via svn and compile SNACS on your system as described in Installation for developers on Debian GNU/Linux.
Download a pre-compiled version snacs-release-svn081_win32.zip from http://sourceforge.net/projects/snacs/files/. Extract the ZIP archive and run SNACS-release.exe from the Windows command prompt. In the actual SVN snapshot, SNACS cannot be started by double-clicking. Open a Windows command prompt instead, go to the snacs/trunk/release directory and start it from there by running SNACS-release.exe:
The release archive ships with example configuration files. Run an example with
SNACS-release.exe -f ../../examples/example_01/example_01.cfg
Click on the start button, to start the simulation.