Just like the web browser version, you have to sync this program with your cellphone by scanning a QR code which you'll be able to do from within Whatsapp on your smartphone. Just tap the icon labeled WhatsApp Web within this apps menu bar. After that, all of your conversations, sessions and contacts will sync and you'll even get to interact with them from your PC without any hassles.
When managing groups, sending and receiving messages you can use the camera that's integrated with your desktop (if there's one available) to send videos and photos that you take. The only limitation is the one we just mentioned; you'll need to have it installed and running on your Android or iOS in order to use it on your desktop.
Windows 8 or higher required.