The gestures are swipe in from the left and swipe in from the right. They're not essential, but they really help usability.
If you're not familiar, swipe from left is fast task switching, similar to alt-tab or double-pressing on the home button in iOS. Swipe from right is charms, which you need to know for settings in Win8 apps but everything else can be found by typing in the search screen.
If you're not familiar, swipe from left is fast task switching, similar to alt-tab or double-pressing on the home button in iOS. Swipe from right is charms, which you need to know for settings in Win8 apps but everything else can be found by typing in the search screen.