When I came home, my dog was on the dining room table and it looked like he didn't know what to do.
When I came home, I found my dog on our dining room table with a really puzzled look on his face.
ーWhen I came home, my dog was on the dining room table and it looked like he didn't know what to do.
「帰宅すると、犬がダイニングテーブルの上にいてどうしてよいかわからなさそうにしていた。」
when I came home で「帰宅すると」
it looked like he didn't know what to do「どうしてよいかわからなさそうにしていた」を使って「途方に暮れる」を表現してみました。
ーWhen I came home, I found my dog on our dining room table with a really puzzled look on his face.
「帰宅すると犬がダイニングテーブルの上で途方に暮れているのを見つけた。」
with a really puzzled look on his face「すごく困った顔で」を使っても「途方に暮れる」を表現できるかと思います。
ご参考まで!