This is the 15797th most frequent Korean word.
본인들이
"본인들이" means "they themselves" or "themselves" referring to a group of people.
In this sentence, '본인들이' emphasizes that the individuals in question are responsible for solving the matter themselves.
본인들이 직접 해결해야 하는 문제입니다.
This is a problem they themselves must resolve.
Here, '본인들이' is used to address a group of people to select something according to their preferences.
본인들이 좋아하는 음식을 고르세요.
Choose the food that you like.
In this case, '본인들이' underscores that the group in reference were the organizers of the event.