Поиск по БД using entityframework in mvc project

Есть таблица в базе данных для нее есть контроллер

namespace MoveApplication.Controllers
{
    public class CostumersController : Controller
    {
        private MoviesDBEntities db = new MoviesDBEntities();
        // GET: Costumers
        [HttpGet]
        public ActionResult Index()
        {
            var costumer = db.Costumers.Include(e => e.CostumerID);
            return View(db.Costumers.ToList());
        }
        [HttpPost]
        public ActionResult Index(string FirstName, Costumers costumers)
        {
            var costumer = db.Costumers.ToList().Where(p=>p.FirstName.StartsWith(FirstName));
            return View(db.Costumers);
        }
        // GET: Costumers/Details/5
        public ActionResult Details(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            Costumers costumers = db.Costumers.Find(id);
            if (costumers == null)
            {
                return HttpNotFound();
            }
            return View(costumers);
        }

во вью прописал

<form id="formSearch" method="post">
    <div class="row" id="SearchBox">
        <div class="col-md-1"> Costumer Name</div>
        <div class="col-md-2"><input type="text" id="FirstName" name="FirstName" /></div>
        <div class="col-md-1"><input type="submit" id="submitsearch" name="Search" /></div>
    </div>
</form>

Почему-то не ищет. Все делал по этой инструкции https://www.youtube.com/watch?v=Ka59HciHBRo&feature=youtu.be