C# :: Adding User Input Into Datagridview Row?

I have a button click that is adding user input into a datagrid view. I am trying to add the information into a row, but the way I am trying is giving me an error. Is there a better way to do this?

private void submitButton_Click(object sender, EventArgs e)
{
Data_Summary form2 = new Data_Summary();
Data_Summary.Rows.Add(firstNameTxtBox.Text, lastNameTxtBox.Text, phoneNumberTxtBox.Text);
form2.Show();
}