executing a stored procedure from my webform

I am working on a simple webpage... I have successfully written the code to add the customer details to the table however it is preferable that i use a stored procedure to do this and I am getting confused. Here is the code as it is now:
protected void btnUpdate_Click(object sender, EventArgs e)         {             SqlCommand command = new SqlCommand();             command.Connection = conn;             command.CommandType = CommandType.Text;             command.CommandText = "UPDATE Customer SET Firstname = '" + txtFirstname.Text + "', Surname = '" + txtSurname.Text + "', Gender = '" + radMale.Text + "', Age = " + txtAge.Text &# ...