Without knowing your knowledge i'm not sure what you want to do exactly.
You can download ren'py itself and something like Editra if you just want to use the art to muck around. That's as simple as using "image *and a picture name*" to define pictures and then "Label start:" to get it running, "show *pic name*" will show the pic, "hide *pic name*" will hide it. don't include the * though . There are tutorials out there but adding text is also fairly simple.
if you want to fully copy this with the right positioning, systems and even the fonts well that's a bit more complex, you'd need to work your way up from the basics but there are probably tutorials for everything if you know what you want to do.