I found this tutorial on Samsung's website. It says Its only for 1 particular model but I have a GT-I9505 (International model) and it worked perfectly!
Android™ File Transfer
Google™ offers a free Android File Transfer application, available from Android.com
, with installation instructions.
Important! You must uninstall Kies for Mac before running Android File Transfer. Otherwise, the application will not connect to your device. <- This is where most people go wrong
To uninstall Kies, download the Kies for Mac software by visiting the Kies website.
From Finder, click Go > Downloads > KiesMac_xxxx.dmg > Uninstall.
After installing Android File Transfer, follow these steps:
Connect your device to your Mac using the supplied USB cable.
Open Android File Transfer on your Mac. Your device should connect automatically and display the contents of your device and optional memory card. You may need to change the USB settings if you cannot connect; swipe your finger from the top of the screen to the bottom to open the Notification Panel and touch Connected as a camera. Touch Media device (MTP) to change the USB settings. The Notification Panel should show Connected as a media device.
Navigate to the appropriate folder containing your music on the Mac.
Select a file or highlight all. Drag and drop the files to your music folder on your device or optional memory card.
The selected music files will now be on your device. Open the Music Player on your device to begin playback.