Just close the app store completely. Double click the button at the bottom and depending what iOS you're using you'll either get vibrating apps at the bottom (if so click the x) or you'll get windows (if so swipe them up).
New to ipads ... we were browsing the app store looking for fairy games when dd accidentally pressed on a war game. That game up on the screen and now we can't get rid of it. I tried touching the app store screen elsewhere but it won't go off and when we go out of the app store and come back in again, the war game screen is still there, with the background app store screen sort of faded out. It is raining and she wants to play fairy games .. help!