Add this code to your Add button click event:
private void button1_Click(object sender, EventArgs e)
{
for (int i = 0; i < checkedListBox1.Items.Count; i++)
{
if (checkedListBox1.GetItemChecked(i))
{
dataGridView1.Rows.Add(checkedListBox1.Items[i], "1");
}
}
}