I will help you by writing the code,
private void button1_Click(object sender, EventArgs e)
{
con.Open();
cmd = new SqlCommand("Insert into SalesDetails Values('" + textBox1.Text + "','" + dateTimePicker1.Text + "','" + textBox2.Text + "','" + textBox3.Text + "','" + textBox4.Text + "','" + textBox5.Text + "','" + textBox6.Text + "','" + textBox7.Text + "','" + textBox8.Text + "','" + textBox9.Text + "','" + textBox10.Text + "')", con);
cmd.ExecuteNonQuery();
con.Close();
MessageBox.Show("Added");
}