NOTE: Check this thread for a guide on how to back up data on the device.

Restore Contacts from SD:

  1. Launch “Contacts
  2. Tap “Menu
  3. Go to “Settings
  4. If necessary, go to “Contacts to display” and switch to “All contacts
  5. Tap “Import/Export contacts” > “Import from SD Card” > “OK

Restore Media Files from SD:

  1. Open “My Files” and select “SD Card
  2. Tap “Menu” > “Edit
  3. Tick the boxes associated with the media files you want to restore
  4. Tap “Menu” > “Move” > “Internal storage
  5. Tap “Move here” or “Create folder” / the folder name to restore the files to a different location
  6. Tap “move here” to confirm

Restore Media Files from a PC:

  1. Connect the Android phone to the PC via USB
  2. Enable “Media device” / “File transfer” on the phone when prompted or from the Notification area
  3. Launch the File Explorer on the computer
  4. Locate the media file backups on the PC storage
  5. Copy and transfer the files to the phone storage, preferably in the folders from where the originate
  6. Once the transfer completes, you can safely disconnect the phone from the USB

Restore Media Files from a Mac:

  1. Connect the Samsung device to the Mac via USB
  2. Enable “File Transfer” / “Media device” on the phone
  3. Launch Kies on the Mac and go to “Back up / restore
  4. Access the “Restore” tab
  5. Tick the boxes associated with “Music”, “Photos” and other media file types you want to restore
  6. Click “Restore” and follow the on-screen prompts to complete the process
  7. Once done, eject the phone storage by dragging and dropping the virtual drive from the desktop and into the trash can
  8. You can safely disconnect the device from the USB port

See More: Samsung Galaxy S9 Plus: Restore Contacts and Media Files