How do I get the datagridview to populate data?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace Point_of_sale
{
    public partial class manageCustomers : Form
    {
        public manageCustomers()
        {
            InitializeComponent();
        }
        SqlConnection Conn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\GARNET6\Documents\inventorydb.mdf;Integrated Security=True;Connect Timeout=30");
        void populate()
        {
            try
            {
                Conn.Open();
                string Myquerry = "select * from CustomerTb1";
                SqlDataAdapter da = new SqlDataAdapter(Myquerry, Conn);
                SqlCommandBuilder builder = new SqlCommandBuilder(da);
                var ds = new DataSet();
                da.Fill(ds);
                CustomersGV.DataSource = ds.Tables[0];
                Conn.Close();


            }
            catch
            {

            }
        }
        private void label6_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }


        private void button1_Click(object sender, EventArgs e)
        {

            try
            {
                Conn.Open();
                SqlCommand cmd = new SqlCommand("insert into CustomerTb1 values('" + CustomerIdTb.Text + "', '" + CustomerNameTb.Text + "', '" + CustomerPhoneTb.Text + "', )", Conn);
                cmd.ExecuteNonQuery();
                MessageBox.Show("Customer sucessfully added");
                Conn.Close();
                populate();


            }

            catch
            {

            }
        }
        private void ManageCustomers_Load(object Sender, EventArgs e)
        {
            populate();
        }

        private void CustomersGV_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            CustomerIdTb.Text = CustomersGV.SelectedRows[0].Cells[0].Value.ToString();
            CustomerNameTb.Text = CustomersGV.SelectedRows[0].Cells[1].Value.ToString();
            CustomerPhoneTb.Text = CustomersGV.SelectedRows[0].Cells[2].Value.ToString();
        }

        private void manageCustomers_Load_1(object sender, EventArgs e)
        {
            populate();
        }
    }
}