I found the solution finally.
- Go to the settings menu on your GS5.
- Scroll down to the "System section and tap "About Device."
- Now scroll down to "Build number."
- Tap the "Build number" section seven times. (You'll see a warning that you're about to unlock developer options.)
- Now back out to the main settings menu, and under "SYSTEM" you'll see "Developer options" listed.
- Under Developer options you select USB debugging
- Now run
adb devices
in the command line and the phone will be visible