Question: how to transfer files from mac to firestick?
Answer: The easiest way is to get a Y cable and thumb drive. This will give you a removable thumb drive on your Firestick.
With a PC on the same network as your Firestick, set up a shared drive. The using a file manager on your firestick (such as MiXplorer or ES Filemanager) connect to the shared drive and transfer the files.