I assume probably the korean speakers might have said;
어제 학교에 갔었고 먹었고 집에 갔어요.
가다(go)-갔다(past)-갔었다(past perfect, it's happening no more-It has more nuance of 'experience')
Okay, I admit it sounds unnatural when you use past(or perfect) tense for every single verbs in one sentence. I also would normally say 지난 일요일에 친구 만나서 밥 먹고* 술 마시고* 헤어졌어요 instead 지난 일요일에 친구 만나서 밥 먹었고* 술 마셨고* 헤어졌어요.
But though it is a bit awkward, it still might be possible anyway I think. But when you use past perfect for every verbs, it sounds to me more like 'listing' than one naturally connected sentence.
So in conclusion,
the book is right. The sentence the Koreans made sounds a bit strange to me,
I would just use past tense only for the last one.
Ich hoffe das hilft dir.