Hello,
First you must add columns to your datagridview like this:
datagridview1.columns.add("Column1");
datagridview1.columns.add("Column2");
datagridview1.columns.add("Column3");
Now you can add rows like this:
datagridview1.rows.add("", "", "");
3 Parameters because your datagridview has 3 columns.
If the datagridview isn't in "readonly-mode" you can edit the data.