Just download the EXE file from Releases tab and run it. You can add multiple excel(.xlsx) files to compare, then press COMPARE button and choose location on your pc where to save the output excel file. It will automatically open and u can see the differences, if a cell is red, then its not the same between all the files, the differences are shown like this in the cell:
1: 2
2: 3
3: 1
1: 2: and 3: is the number of file that you imported, and after : is the value in this sale in the file