Are you reading the ID, Name, and Amount into the datatable, then want to loop through it, gather data from somewhere else, and add the new data in C1 and C2? If this is correct, then after reading the ID, Name, and Amount into a datatable you use Add Data Column to add the C1 and C2 columns, and then inside your For Each Row in Datatable you just use Assigns to set the value of C1 and C2 for the current row.