How to make login form using Asp.net MVC and Sql Server

Admin Controller Code: 

 onlinemarketingEntities1 db = new onlinemarketingEntities1();

        [HttpGet]

        // GET: Admin

        public ActionResult Login()

        {

            return View();

        }

        [HttpPost]

        public ActionResult Login(adminn adm)

        {

            adminn ad = db.adminns.Where(x => x.ad_name == adm.ad_name && x.ad_password == adm.ad_password).SingleOrDefault();

            if (ad!=null)

            {

                Session["ad_id"] = ad.ad_id.ToString();

                return RedirectToAction("Category");

            }

            else

            {

                ViewBag.error = "Invalid User Name or Password";

            }

            

            return View();

        }

Login View Code:

@model onlinemarketing.Models.adminn

@{

    ViewBag.Title = "Login";

}

@using (Html.BeginForm())

{

<form action="" method="post">

    <div class="imgcontainer">

        <img src="img_avatar2.png" alt="Avatar" class="avatar">

    </div>

    <div class="container">

        <label for="uname"><b>Username</b></label>

        @*<input type="text" placeholder="Enter Username" name="uname" required>*@

        @Html.TextBoxFor(x => x.ad_name, new { @class = "form-control", @placeholder = "Admin Name" })

        @Html.ValidationMessageFor(x=>x.ad_name)

        <label for="psw"><b>Password</b></label>

    

        @Html.PasswordFor(x => x.ad_password, new { @class = "form-control", @placeholder = "Password" })

        @Html.ValidationMessageFor(x => x.ad_name)

        <input type="submit" value="submit" class="btn btn-default" />

    </div>

    <div class="form-group">

<p style="color:red">        @ViewBag.error  </p>

    </div>

</form>

}

@section scripts

{

    

<script src="~/Scripts/jquery.validate.js"></script>

 

    }