내일에 집에서 잘 거예요. (X)
내일 집에서 잘 거예요 (O) – I will sleep at home tomorrow.
Words like 오늘(today), 어제(yesterday), 내일(tomorrow) cannot be marked with time particle “에.” It is used on its own.
Other choices :
월요일부터 금요일까지 일을 해요. – I work from Monday to Friday.
어제 동생이랑 집에 있었어요. – I was at home with my younger sibling.
많은 사람들이 파티에 참석했어요. – A lot of people participated in the party.