1. Open Settings app on your old device.

2. Tap 'Settings' > 'Chats/Groups' > 'Chat Backup'.

3. Check 'Automatically backup when connected to Wi-Fi' and choose how frequently you want the backups taken (daily, weekly or monthly).

4. Tap Back Up Now button at bottom right corner of this screen with three horizontal lines icon next to it.

4a) If prompted enter your passcode then tap Continue.

5' Wait for the process completes successfully; depending upon size & internet speed could take anywhere between few minutes up till several hours depending on both factors mentioned above.

Now let's proceed towards transferring these backed-up chats over to Android device:

Open Play Store (Google App Store if using Samsung Galaxy series).

Search 'WhatsApp' and install latest version available from results list.

Launch newly downloaded app followed by agreeing terms & conditions screen appeared next.

6' Tap 'Restore chat history' option when prompted during initial setup process.

This will open up a new window displaying all backed-up conversations along with an 'Import' button alongside each one - tap on that respective entry corresponding to desired conversation you wish restore onto your Android device.

Wait for the restoration procedure to finish completely; once done, check inside WhatsApp app under Chats tab where restored chat should now be visible among other conversational entries.

Whatsapp android to iphone free