retina display resolution question

[REDNSX]

This might seem like a stupid question because I don't know how it will work yet.

If I want to make my game display 960×640 pixel resolution "Retina Display" do I just have to export my file at that resolution? Will that work? The other question is will we have to upload 2 files to apple one with normal display and one with retina display resolution. For me personally if all I have to do is upload a file that is 960×640 it will be easer because my game will benefit from all the extra screen display so I have more room to work with in a way.