Open WhatsApp on your phone
Verify the phone number matches the one used for the backup
Reinstall WhatsApp if needed
Follow the setup prompts
Tap Restore when prompted to restore chat backup
Wait for the restore process to complete
Tap Next after the chats are restored
Allow media to finish restoring in the background
Make sure Google Drive backup is enabled on Android or iCloud backup is enabled on iPhone
Use the same Google account on Android or Apple ID on iPhone that was used for the backup
Ensure the device has enough storage and a stable internet connection