$ mkdir nnbar-calo-sim-build
$ cd nnbar-calo-sim-build
$ cmake -DGeant4_DIR=path_to_Geant4_installation/lib/Geant4-10.0.0/ ../nnbar-calo-sim
$ make
$ source path_to_Geant4_installation/bin/geant4.sh
$ ./nnbar-calo-sim
$ ./nnbar-calo-sim -m nnbar-calo-sim.in