In some cases, the sheet number information starts with string or a char, like "P001", "P002" or "FOLD1", "FOLD2". In this case add this part here. With the example before, add "P" or "FOLD".
Side indicator. It could be "_F / _B" or "_Front / _Back" or "A / B" etc. When there is no such indicator but the sheet number identifies the side, select from the check box either %Even% or %Uneven% for the sides.