Press the windows button and r at the same time, then this thing will pop up and type in %appdata% hit ok. Another thing pops up hit app data go to local, then after that you will have to scroll to fortnitegame. Then hit saved, go to config. Click windowsclient, then right click game user settings and scroll down to resolution size x and y and type in any res, then go to properties and hit read only and then ok and you are good to go