I am new to this. My understanding is once I submit my paper layout(stack,) I cannot move the papers around. I notice in day two, people have moved their papers. Am I misunderstanding this?
you're right with both - your assumption and your observation... even if this really is confusing...
Day 2 was a big exception from the rules this month. There had been a lot of different interpretations of the day 1 instructions, so I clarified and expanded them on day 2 and allowed for adjustment. But - as I said - this was a one time exception.
The rules are: once something is placed it may not be moved during the PS. You're always welcome to change your page afterwards.
Hope that helps!