Mapping table is empty - mysql

Question

Below are two tables that has a many to many relation and and also another table that has a relation with the two first. A mapping table is created by Visual Studio with the name OrderEmployee, but when I run the application and enter some information to the Timeunit create form, the mapping table OrderEmployee is empty!
Should there not be some IDs added to that table since it has a relation with the Timeunit table or how is this mapping table thing working, when will there be data added to the mapping table? Or is something wrong with my Entity Classes?
public class Order
{
public int ID { get; set; }
public string Name { get; set; }
public int? ManufacturerID { get; set; }
public virtual Manufacturer Manufacturer { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
public class Employee
{
public int ID { get; set; }
public string Name { get; set; }
public int EmployeeNumber { get; set; }
public virtual ICollection<Timeunit> Timeunits { get; set; }
public virtual ICollection<Order> Order { get; set; }
}
public class Timeunit
{
public int ID { get; set; }
public int Week { get; set; }
public int HoursPerWeek { get; set; }
public int EmployeeID { get; set; }
public int? OrderID { get; set; }
public virtual Employee Employee { get; set; }
public virtual Order Order { get; set; }
}
EDIT:
Create Method for Timeunit:
public ActionResult Create([Bind(Include = "ID,Week,HoursPerWeek,EmployeeID,OrderID")] Timeunit timeunit)
{
if (ModelState.IsValid)
{
db.Timeunits.Add(timeunit);
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.ProjectID = new SelectList(db.Orders, "ID", "Name", timeunit.OrderID);
ViewBag.ResourceID = new SelectList(db.Employees, "ID", "Name", timeunit.EmployeeID);
return View(timeunit);
}