NOTE: You can check this thread for instructions on how to back up data from the phone.

Restore Contacts from SD Storage:

  1. Open “Contacts
  2. Tap “Menu” > “Settings
  3. Go to “Contacts to display” and select “All contacts
  4. Tap “Import/Export contacts
  5. Go to “Import from SD card” and tap “OK

Restore Media Files from SD Storage:

  1. Open “My Files
  2. Go to “SD Card
  3. Tap “Menu” > “Edit
  4. Tick the boxes associated with the media files you want to restore
  5. Tap “Menu” > “Move” > “Internal storage
  6. Tap “Move here” > “Create folder
  7. Select the desired folder
  8. Tap “Move here

Restore Media Files from a Windows PC:

  1. Connect the Android device to the PC via USB
  2. On the phone, enable “Media device” or “File Transfer” when prompted or from the Notification shade
  3. Launch the File Explorer on the PC
  4. Copy and paste the files to the phone storage, preferably in the folders of origin
  5. once done, eject the phone storage and safely disconnect the device from the USB port

See More: Samsung Galaxy J6+: Restore Contacts and Media Files