1 - This is how the time was spent. (I would use a comma after "day.")
2 - This was the purpose of our being there.
Take a different example.
1b. I sat at the bus stop for an hour, reading my book
2b. I sat at the but stop for an hour to read my book.
Do you see how 2b says I went there for the purpose of reading? While 1b says that's what I did while I was there?
[a writer, not a teacher]
Student or Learner