This is the same formula but based upon input data held as a table and is a dynamic array version = SUMIFS( DataTable[Amount], DataTable[Month], MONTH(mnth&1), DataTable[Description], Description )
The formula is entered into cell Overall!C8 and spills to populate the output range.
Excel is Fun. try this one also
Copy the formula and paste in Overall sheet cell C8 and drag over and down.
=SUMPRODUCT(('Data List'!$C$4:$C$17=$B8)*(('Data List'!$F$4:$F$17)>=C$5)*(('Data List'!$F$4:$F$17)<=EOMONTH(C$5,0))*'Data List'!$G$4:$G$17)