You can install Whatsapp in your PC by downloading the desktop edition of whatsapp found in this link:
When you install whatsapp on your PC, it will ask you to sync it using your phone. There is a QR Barcode that displays in the Whatsapp PC app.
From within Whatsapp on your phone, click on Settings (bottom right), then click on WhatsApp Web/Desktop. Then you press on Scan QR Code. Place the camera where you se the QR Barcode on your computer screen, and that should activate Whatsapp for your PC.