To add new records into a dataset, a new data row must be created and added to the DataRow collection (Rows) of a DataTable in the dataset. The following procedures show how to create a new row and insert it into a DataTable. Examples are provided for both typed and untyped datasets.
I created this Dataset (view picture).
dsOperation dt = new dsOperation();
DataRow opRow = dt.Tables["Operations"].NewRow();
opRow["Group"] = "FirstGroup";
opRow["SubGroup"] = "SecondGroup";
opRow["Debit"] = 0;
opRow["Credit"] = 10;
dt.Tables[0].Rows.Add(opRow);