You will need to include some JavaScript to your code. Here are some examples on how to use it.

 <button onclick="myFunction()">Click me</button> 
 <element onclick="myScript"> 
 object.onclick = function(){myScript}; 
 object.addEventListener("click", myScript);

I would also recommend using technologies like bootsrap or angular to deal with menus and navigation bars. They make life easier and is good to know how to use them.

If you want to make it so that when you click something them menu is visible, you could use the onclick function in the href and toggle the visibility of the menu using css display: non or block.

HTML: you are creating a div with the css properties of that class and assigning it an id. you are also creating a link that will call the javascript function when clicked

<div class="menu-subs" id="menu">
// the menu
</div>

<h1 onclick="openMenu()">Open menu</h1>

CSS: the class which is not displayed currently

.menu-subs, .menu-column-4 
{
    display: none; 
}

Javascript:

function openMneu(){
    //get the menu element in the html
    elem = document.getElementById("menu");

   // set the styling of the menu to visible
   elem.style.display = "block"; //or inline block depending on your other css
}

when openmenu is called by the clicking of the heading open link. You could also use element.addeventlistender, bit that would be a bit harder, so i suggest you try this. This should work, lmk if it does

(this is my second stackoverflow answer :|)