Circle Pad and Touch can be either JOYSTICK or MOUSE,
Buttons can either be a letter for example B, or a special key, like SPACE, CLICK, RIGHT CLICK, ENTER, BACKSPACE, SHIFT, TAB, LEFT, RIGHT, UP, DOWN, PAGE UP, PAGE DOWN, or WINDOWS,
Throttle controls the delay between checking for new packets (in milliseconds), a high number will have slightly more lag between pressing a button on the 3DS and receiving it on the PC, however will make the application use less CPU. In my experience, 20 is a reasonable throttling amount.