how to get sprite to move when you drag screen

I AM VERY NEW TO LUA AND NEED HELP ASAP
so for example if you move your finger left across the screen the sprite will follow your finger and when you release your finger it
stops moving oh and it starts when your finger is on the screen

hi again,


function setup()
    -- look at the Codea examples ^^
    img = readImage("Planet Cute:Character Boy")
end

function draw()
    background(0)
    sprite(img, CurrentTouch.x, CurrentTouch.y)
end

cheers