Need instructions.

I enjoy this game (good brain exercise), however it's extremely frustrating to play on a laptop or touchscreen. Using a mouse it would be easy to click left for "check" or click right for "x". I haven't discovered a way to swap between on touchscreen. And when using laptop touchpad, it seems to be overly sensitive mistaking a "right click" for a "right click" (touchpad tap). It would be great to have a "toggle" selection between "check" or "x". Then a click or touch would enter the selection.