I downloaded retroarch Fromm cydia and downloaded a n64 rom and ran it, the buttons where the SNES controls and didn’t work. So then I tried to fix it and messed a bunch of files up while trying to do so. Is there any way to restart retroarch as if I got it brand new?
You need to remove all cfg files created by the application. To do so and as you are in iOS you can use ifunbox to access the /var/mobile/Documents/.RetroArch folder where all these cfg are stored. More easily, remove the entire .RetroArch folder and you are done as it were new!
You can also use iFile to remove them, it depends what is easier for you.