Hi, you can try this steps. Thanks!
Back up media & pictures
To back up your media and pictures, follow these steps:
Note: You must have a SD card installed.
1. From any Home screen, tap the Apps icon.
2. Tap My Files.
3. Tap All files.
4. Tap sdcard0.
5. Choose one of the following options:
• To copy all of your files, tap check box next to sdcard0 to select all files.
• Locate the media and picture files you want to back up. To the left of the desired file or folder, tap the check box to select the check box. Repeat as desired.
Note: Pictures and movies captured using the Camera application are stored in the DCIM folder and media may be stored in the Download folder or other folders.
6. Tap the Copy icon in the top-right.
7. Tap extSdCard. .
8. If necessary, navigate to the desired folder.
9. Tap Paste here.