Depends.... savegames are always named like this:
5-3-LT1.save
5 ~ stands for the page
-3 ~ stands for the slot (in this case the 3rd slot, from top left to bottom right)
-LT1.save ~ always ends in the same thing.... whatever the LT1 stands for I don't know it yet
So if you downloaded a savegame from somewhere around here it usually gets renamed to something like this:
12345_5-3-LT1.save
you'd have to remove the 12345_ in front of the 5-3-LT1.save else the savegame won't be found by ren'py