Hi Destinykid,
Change the GetCustomers method with below.
private CustomerModel GetCustomers(int currentPage)
{
    int maxRows = 10;
    CustomerModel customerModel = new CustomerModel();
    customerModel.Customers = PopulateCustomers()
                .OrderBy(x => x.CustomerID)
                .Skip((currentPage - 1) * maxRows)
                .Take(maxRows).ToList();
    double pageCount = (double)((decimal)PopulateCustomers().Count() / Convert.ToDecimal(maxRows));
    customerModel.PageCount = (int)Math.Ceiling(pageCount);
    customerModel.CurrentPageIndex = currentPage;
    return customerModel;
}
private static List<Customer> PopulateCustomers()
{
    string constr = @"Data Source=.;Initial Catalog=Northwind;uid=sa;pwd=pass@123;";
    List<Customer> customers = new List<Customer>();
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT CustomerID,ContactName,City,Country FROM Customers"))
        {
            cmd.Connection = con;
            con.Open();
            using (SqlDataReader sdr = cmd.ExecuteReader())
            {
                while (sdr.Read())
                {
                    customers.Add(new Customer
                    {
                        CustomerID = sdr["CustomerID"].ToString(),
                        ContactName = sdr["ContactName"].ToString(),
                        City = sdr["City"].ToString(),
                        Country = sdr["Country"].ToString(),
                    });
                }
            }
            con.Close();
        }
    }
    return customers;
}