Asus BU401LG - Manual (Page 45)

Notebook PC E-Manual 
Windows ® UI
Windows® 8 comes with a tile-based user interface (UI) which allows
you to organize and easily access Windows® apps from the Start screen.
It also includes the following features that you can use while working
on your Notebook PC.
Start screen
The Start screen appears after successfully signing in to your user
account. It helps organize all the applications you need in just one
place.
Zoom in/out button
Windows® Apps
These are apps pinned on the Start screen and displayed on tiled-format
for easy access.
NOTE: Some apps require signing in to your Microsoft account before
they are fully launched.