How do I add a a dropdown menu in the default asp .net 3.1 razor templ

Question

By default, when you create a page in asp .net core 3.1 (in Visual Studio of course) you get a base menus in _layout.cshtml:

<nav class="navbar navbar-expand-sm navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3">
    <div class="container">
        <a class="navbar-brand" asp-area="" asp-controller="Home" asp-action="Index">Axinco.JuryTool.Interface.Gui</a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target=".navbar-collapse" aria-controls="navbarSupportedContent"
                aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="navbar-collapse collapse d-sm-inline-flex flex-sm-row-reverse">
            <partial name="_LoginPartial"/>
            <ul class="navbar-nav flex-grow-1">
                <li class="nav-item">
                    <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
                </li>
            </ul>
        </div>
    </div>
</nav>

This gives you the following layout:

 

 

I added code to download extra menu settings based on the role. Basically, it's a menuheader (for example 'Adminisrator') and then a couple of menu items.

 

So I want to add a down menu next to "Privacy".

 

How would I best do this?