It's basically a scuffed local messenger. As long as you're connected to CSMwireless you'll be able to message everyone connected.
ON WINDOWS: It will likely tell you that the program was blocked, just hit "More Info" > "Run Anyway"
ON MAC: It will likely not let the program run due to being from an "unidentified developer." After you get this message just go to "System Preferences" > "Security and Privacy" > And then just allow it to opened from the bottom of that page.