How to add row in an excel sheet

I have an datatable which i m printing in an excel sheet.But in a excel sheet first i want to add legends then my datatable should be there.But at first only i have printed my datatable then how do i add rows to write the legends

@Doonline ,

Create another datatable with same columns, else insert a row in the existing datatable and add your legends in it. If you are planning to have a new datatable for the legends then write that first to excel then you can write your existing datatable by using a start range value