To change the Live Wallpaper image you should do double click on the image. Also you can do it from the options menu too, where you can also configure the speed, transparency...
To INSTALL: You should open the application and press the menu button and select the option to "Set Live Wallpaper". You can also do this from the android menu, looking for the option of Live Wallpapers and then selecting it.
3D Taiwan Cube Flag LWP
This app has access to :