WhatsApp for Samsung Galaxy A8

Open the Google Play Store, search for WhatsApp Messenger, and tap Install (on the A8 the Galaxy Store can serve as a backup source if Play Store has issues). Open the app, accept the terms, enter your phone number with the correct country code, and verify the 6-digit SMS code. Allow the contacts and media permissions when One UI prompts so your chats and address book sync correctly. See how others solved this on Reddit

Google Drive only stores one WhatsApp backup per phone number, and a Dual Messenger clone is a separate app instance that Drive treats independently, so it often won't see the backup made by your primary WhatsApp. Make sure the Google account holding the backup is signed in on the phone (Settings > Accounts and backup > Manage accounts) and selected in WhatsApp under Settings > Chats > Chat backup > Account. The backup also only restores during first-time verification, so restore immediately after you enter and verify the number in the clone, before finishing setup. See how others solved this on Reddit

WhatsApp mirrors your phone's address book, so numbers synced from Google or Samsung accounts (or auto-saved by other apps) can appear as WhatsApp contacts. Go to Settings > Accounts and backup > Manage accounts and turn off Contacts sync for any account you don't want, then delete the unwanted entries in the Samsung Contacts app. Because WhatsApp reads contacts through the Android Contacts permission, the cleanest way to limit what it sees is to control which contacts your phone stores rather than expecting a separate toggle inside WhatsApp. See how others solved this on Reddit

Samsung Smart Switch and Google's migration tool often skip custom/third-party stickers and some app caches, so do a proper WhatsApp chat backup before moving. On the old phone open WhatsApp > Settings > Chats > Chat backup and back up to Google Drive, then on the A8 install WhatsApp, verify the same number, and tap Restore when prompted. Re-add any third-party sticker packs from the Play Store afterward, since those aren't included in the Drive backup. See how others solved this on Reddit

Android Auto only surfaces WhatsApp once it has notification access, so open Settings > Apps > Special access > Notification access and confirm Android Auto is allowed. Open the Android Auto app's own settings and check that WhatsApp is enabled in its list of messaging apps, and update both WhatsApp and Android Auto from the Play Store. If it still doesn't appear, clear Android Auto's cache in Settings > Apps > Android Auto > Storage and reconnect to the car. See how others solved this on Reddit

When the Samsung Contacts app misbehaves, WhatsApp can't read your address book and shows an empty list. Go to Settings > Apps > Contacts > Storage and tap Clear cache (use Clear data only if you have a contacts backup), then restart the phone. Confirm WhatsApp has the Contacts permission under Settings > Apps > WhatsApp > Permissions, and re-enable account sync in Settings > Accounts and backup > Manage accounts so your contacts repopulate. See how others solved this on Reddit