if you are asking about in add data row how to add to specific column then use below
{"","","Third","Fourth","","","","","","Ten"}
this will add data in the respective columns with other columns being empty
here you need to build a table with 10 columns
Hope this helps
if you want to add to already existing datatable then you need to loop through that table or lookup on that table with a unique column and get the row id and then use assign dt.Rows(LookedupID)("ColumnName") = "Value to be populated"