Install WhatsApp on the new phone
Open WhatsApp and verify the same phone number used on the old phone
Allow WhatsApp to access contacts, photos, and files if prompted
When prompted, tap Restore from backup
Wait for the chat backup to download and restore
Keep the phone connected to Wi-Fi and power during the restore
If using Android, make sure the Google account with the backup is added to the new phone
If using iPhone, make sure the same Apple ID and iCloud account are signed in
If no restore prompt appears, check that a backup exists on Google Drive or iCloud
If needed, uninstall and reinstall WhatsApp, then verify the number again
After chats restore, wait for media files to finish downloading
Open WhatsApp and confirm your messages are back