How does the visualization and return particles work in Geant4 for CRY Library?

I am using the CRY Library to generate events in Geant4. But I cannot visualize the sub box for cosmic ray generation in Geant4 world volume and so cannot get any idea on how and where does the cosmic rays get generated.

Also, I’m not getting the idea of “return particle” command. Like, when we generate say, 10K events and apply “returnNetrons 1” command with others set to 0, whether 10K neutrons are generated or out of 10K all particles, only the neutrons are detected.