Installation question...

Hey, I hope this is allowed. I am a MacBook user and I'm trying to install this program that's suppose to be a PS plug-in...when I double click the .zip file it gives me an .exe file...But when I click on that, all it does is tell me it can't be read. Anyone know what I'm doing wrong/what I have to do/what program I have to use to get the thing to read and install? Any help is greatly appreciated.
Thanks! :)