Datatable using LINQ

1.Read Excel(3 Sheets - PrevMonth(Columns: ID,Product,Citya and Sales), CurrentMonth(ID,Product,Citya and Sales) and Comments(ID,Product,City and Commets).
2.Need to store all in Datatables.
3.Concatenate Columns ID,Product,City as “Product Details” Column and Sum Sales GroupBy Product Details and stored in “Amount” Column.
4.Remove duplicates.
5.Compare Previous month sales Amount and Current Month Sales amount.
Please find attached excel for the more infoSample_Input_Data.xlsx (14.9 KB)