To install WhatsApp on your Windows Phone, download the app starts. Therefore, in the application list, click on the icon in the app store.
Once in the store, click on the magnifying glass symbol that appears at the bottom of the screen. It is the search engine.
A blank field opens to find what you want. Write "whatsapp" (without quotes) and give it back to the lens.
The smartphone will offer a list of applications that match your criteria. The first should be Whatsapp. Click on it.
The tab for the app opens. At the bottom of the screen, you'll see a button with the word "Install". Click on it.
The app will begin downloading Whatsapp. Now just have to wait until it is installed to start using it.