This is a good how-to:
http://www.ubuntu.com/download/desktop/create-a-usb-stick-on-mac-osx
This is a good how-to:
http://www.ubuntu.com/download/desktop/create-a-usb-stick-on-mac-osx
http://osxdaily.com/2014/10/16/make-os-x-yosemite-boot-install-drive/
Tried bunch of other posts but none of them worked.