Follow our easy instruction and install the official version of whatsapp on your samsung z4 click on the big blue download button on this page and press ok to save an apk file swipe down to open your bottom panel after finishing downloading click on the file name press on the install button and enjoy your new app!. Download whatsapp z4. How to download whatsapp this wikihow teaches you how to download the free whatsapp app onto your iphone or android, as well as how to download and install the whatsapp desktop program on a windows or mac computer once you've downloaded.