Not a silly question at all!
First up - What flying machine are you building?
Have you downloaded the correct software assistant? Are you running a NAZA M Lite or NAZA M V2 (or a Phantom..) or Wookong M for your flight controller? The software assistant is different for each.
Reboot your Mac...
Hey Derek,
NAZA M software became available the day after you initially posted. Available here - http://www.dji.com/product/naza-m-v2/download
I've been running the assistant software on my Mac successfully. You'll note that the firmware updates are available within the assistant software...