It accepts a criteria range, one criterion, and an optional sum range, and that is the entire function. SUMIF puts the sum range last and treats it as optional. Everything after that opening argument is a criteria range paired with a criterion, and Excel accepts up to 127 of those pairs. Set the sum range to the Amount column, because SUMIFS wants the numbers you are adding before it wants any conditions. SUMIFS needs every criteria range to match the sum range in size.