welcome to the forum. and good job for posting a sample excel file. another thing you could do is to input the desired answer so that we don't have to second-guess if what we are doing is correct or not. you may look at my signature to upload an eg that is easier to understand.

try this in Sheet2 cell E2
=SUMIFS(Sheet1!C:C,Sheet1!A:A,A2,Sheet1!B:B,B2)