Transferring files applications via USB on Mac

I have Nexus 5 and I'm using the Android File Transfer as explained on Google's official support: [Transfer files between your computer and Android device](https://support.google.com/nexus/answer/2840804) . However, after either copying zip archives or creating new folders in the file transfer window with my Nexus 5 connected via USB, I do not see the changes reflected on the device. What am I missing?