We only planned to stay in Valencia for 2 nights, so on what was meant to be our last night, we went out for some traditional Spanish cuisine.

so on what was meant to be our last night 해석이 어떻게 되는지 특히 so on what에 대해서 알려주시구요 왜 그렇게 해석되는지좀 알려주세요!!!