How do I manually populate ViewModel (Not using AutoMapper!)

I know there are a lot of posts on the subject but I cannot find one that helps me do what I want. I know that I will eventually be using Automapper but before I start playing with it, I want to learn how to do things manually. I want to create a ViewModel, populate it with values from my entities by way of a repository and send it to my View. As simple as this sounds, I am stuggling to get it done. I'm using MVC 3, EF 4.3, Database First. I have auto-generated my classes. I'm posting the relevant entities (abbreviated/renamed for this post) and classes, here is what I have so far:

Aggregate Entity: Shipping Header

using System;
using System.Collections.Generic;

namespace My.Models
{
public partial class ShippingHdr
{
    public ShippingHdr()
    {
        this.ShippingLI = new HashSet<ShippingLI>();
    }

    public int ID { get; set; }
    public int ShipToSiteID { get; set; }
    public Nullable<System.DateTime> DateShipped { get; set; }
    public Nullable<System.DateTime> EstDeliveryDate { get; set; }
    public string FromSitePOC { get; set; }
    public Nullable<int> ShipperID { get; set; }
    public string TrackingNo { get; set; }
    public string Comments { get; set;}
    public virtual Shippers Shippers { get; set; }
    public virtual ICollection<ShippingLI> ShippingLI { get; set; }
}

}

Here is my ViewModel

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace My.Models.ViewModels
{

public class ShippingHeaderSummaryVM
{
    public int ID { get; set; }
    public string Site { get; set; }
    public Nullable<System.DateTime> DateShipped { get; set; }
    public Nullable<System.DateTime> EstDeliveryDate { get; set; }
    public string TrackingNo { get; set; }
    public string HeaderComments { get; set; }
    public string Shipper { get; set; }
    public int NumOrders { get; set; }
    p