Step #1. Install WhatsApp Web Enabler from BigBoss repo for free.

Step #2. Once you have installed this tweak, launch Settings app

Step #4. You will see the kill switch right on top on the tweak. Switch on the enable button.

Step #5. Launch WhatsApp.

Step #6. Tap on Settings from the bottom right corner.

Step #7. Tap on WhatsApp Web.

Step #8. Go to web.whatsapp.com on your computer and scan the QR code.

Step #9. Once the QR code is scanned, you can access WhatsApp from the web browser.