To my understanding
#include "Wed3182Character.h"
class AActor* OtherActor;
AWed3182Character* MainCharacter = Cast<AWed3182Character>(OtherActor);
is the method of creating the reference that allows GameInfo to know about MainCharacter. MainCharacter being a stand in for AWed3182Character. What more is needed? I do not know what other details to tell you.