You need to enable USB Debugging in the developer options. To do this you need to go to Settings-> About device-> Software info-> then tap on build number seven times. Back-out untill you see a new option labeled Developer options. In developer options look for USB Debugging. Now, when you plug your device in (Also make sure it is unlocked before doing so.) your devices notification panel will have debug options. Select data transfer (It may be labeled something else). The option you are looking for should have a sub-caption that says it will allow data transfer betwern the device and the computer. Hope this helps. P.S. when your phone is unlocked and connected, swipe-down your notifications and tap the USB icon, then select media/file transfer.