Go to www.samsung.com on your computer.
Find the download section on the website to download Samsung Kies 3.
Download and install Samsung Kies 3.

Open the cover at the bottom of your mobile phone.

Connect the data cable to the phone socket and to your computer's USB port.

Slide your finger down the display starting from the top edge of your mobile phone.
Tap Connected as a media device.

Tap Media device (MTP) until the function is turned on.

Start Samsung Kies 3 on your computer.

Click your mobile phone on the list of connected devices.

Click Back up/Restore.

Click Select all items to select all files.

Click Backup.

Click OK.