LCD Breakout question

I have a question, So i totally get that the Nintendo DS touchscreen plugs into the connector and then the connector needs a breakout or soemthing. I just don't understand what that means. the x1 x2 and y1 y2 get the position of a touch right? But doesn't that only need an x and a y?
heres the break out: http://www.sparkfun.com/products/9170
and then theres the screen http://www.sparkfun.com/products/8977
I also don't get how the screen gets the information on what to display if the only pins coming out are position things.

A little help?