、。
After dinner, we all went to the reception room.
Literal
Dinner-of after, we [topic-は] everyone reception-room [to-に] go-[past-った].
応接室 ('reception room, drawing room') is a traditional domestic room in larger Japanese homes — the formal space where guests are received, distinct from the family's everyday 居間. Less common in modern apartments but still a recognizable cultural term. みんな ('everyone, all') here modifies the topic 私たち, emphasizing that the whole group moved.