LG 42PM4700 Owner's Manual page 172

✎ You can purchase apps from PC or TV but you must use TV to install and run
them.
✎ If you have insufficient storage space on TV, you can download apps to USB
storage device connected through the TV's terminal for USB apps. The app
stored on USB is available to run/delete/move from
✎ The USB storage device containing apps cannot be used for saving other
data. (For USB Apps Only)
My Apps screen.