WhatsApp announced their desktop apps for PC and Mac, which is nothing more than a web wrap of WhatsApp Web but with notifications directly in your computer.
Opening the app presents you with the same UI that you find in WhatsApp Web. The login process is also similar, you open WhatsApp in your phone and scan the QR code, voila ! All your chats are synced to your desktop.
The application has a set of options in the menu bar. Under WhatsApp menu you have "new chat", "new group", "Profile status" and "Log out" which are pretty obvious and useful. The "+" sign also allows you to start a new chat with your contacts.