Bought a slightly used bike. FD would not shift onto the smallest ring, and chain was touching FD when middle front/smallish rear. I watched few youtube clips that all followed the same theme. I then made my attempt. While trying to reattach the shifter cable, I can't get it right. Either it is too slack or too stiff to shift onto the large ring. I've taken it off and reinstalled it so many times that the cable is starting to fray. I'm frustrated. Any helpful advice? Shimano Sora, by the way.

Thanks!