I  have the cgo2+  in  my  Q500,  and   I've  been  just taking the SD card out and   doing it manually in my laptop..

However,    I see your   cgo3  can be done also  via  the wi-fi  method.     If  you have  done a lot of  video  in 4K,     it's going to be  slower than  direct   downloading the  SD card.

here is how to   do the  wifi  method

http://yuneec-forum.com/threads/how-to-download-video-files-from-the-cgo3-using-wifi.1262/

edit!   I KNEW  I remembered   a  tidbit about  the  cgo3! 

" the usb port  on the camera is not  functional as of  yet"        So,  for now,      either  take the  SD card out,  or  configure your  Mac  to   use  the wi-fi  method.