Cascading Dropdown list MVC5 using fluent nhibernate

I have read for 2 days every single question that looks like my problem on here and read multiple pages and tutorials and even watched videos and i just can't understand it or make it work... What im trying to do is that i have 2 dropdown lists, one is "Departamentos" which you can think of it as a state and "Municipios" which you can think of it as a county. What i need and no matter what i just CAN'T make it work is that when i select a departamento ONLY the municipios from that departamento show up on the dropdown list. Im really a complete noob regarding programming and unfortunately i think i started with something way too big for me, so i' sorry if this is a basic really easy thing to do for you.

The departamento class is :

public virtual int id_departamento { get; set; } public virtual string descripcion { get; set; } //i specify Relationship for fluent Nhibernate to municipios since it is a 1-n public virtual IList<Municipios> Municipios { get; set; }

The municipio class is :

public virtual int id_municipio { get; set; } public virtual string municipio { get; set; } public virtual int id_departamento { get; set; }//THis is the FK from Departamento

And heres my main class Sitios where i connect everything to: This is for the Nhibernate relationships

public virtual Departamentos Departamento { get; set; } public virtual Municipios Municipios { get; set; }

This is for the lists on that same Sitios class:

public virtual List<Departamentos> Departamentos { get; set; } public virtual List<Municipios> municipiosLista { get; set; }

Now going to MVC this is the controller i have for the Get create where i populate the lists of Departamento and Municipio to be shown:

using (ISession session = NhibernateHelper.OpenSession()) { var deptos = session.Query<Departamentos>().ToList(); var munis = session.Query<Municipios>().ToList(); var instanciadelacopia=new Sitios { Departamentos = deptos,                  municipiosLista = munis                             }; return View(instanciadelacopia); }

And the create view for that specific dropdown part:

@using (Html.BeginForm()) { @Html.AntiForgeryToken()  <div class="form-horizontal"> 
Sitiosh4> <hr /> @Html.ValidationSummary(true, "", new { @class = "text-danger" }) <div class="form-group"> <label class="control-label col-md-2"> Departamento label> <div class="col-md-10"> @Html.DropDownListFor(model => model.id_departamento, new SelectList(Model.Departamentos, "id_departamento", "descripcion"), "--Select--", new {@id = "depto"}) div> div> <div class="form-group"> <label class="control-label col-md-2"> Municipio label> <div class="col-md-10"> @Html.DropDownListFor(model => model.id_municipio, new SelectList(Model.municipiosLista, "id_municipio", "municipio"), "--Select--", new { @id = "muni" }) div> div>

Everything works fine since it brings me all the values for me to select from the db, where i'm stuck and can't advance is that i need a cascading dropdown for the municipios list that when i select certain departamento ONLY the municipios of THAT selected departamento show up on the list. So for example i select departamento "atlantida" which it's ID is 1 then only the municipios which have that foreign key from Departamentos = 1 are shown which im guessing Jquery is required.

Would be really good if someone can help me with this, i feel so stressed since i just cant figure out what i need to do. Thanks

All examples i've seen are about using JSON like this one: http://www.c-sharpcorner.com/uploadfile/4d9083/creating-simple-cascading-dropdownlist-in-mvc-4-using-razor/ but since i already have all the data available on the dropdowns i think i don't need that and instead just a plain jquery function which i cant create.