I suggest you to have a base html like this:
<body>
<div id="popup"></div>
<div id="content"></div>
</body>
And have your "screens" in separate html documents, and when you push a button, refresh your base html according, this way:
//on click
$('#content').html('');
$('#content').load('mynewcontent.html');
Samsung applications work with single page web app philosophy, so you must refresh the base html dynamically.
If you need to create a popup, there are lots of tutorials about how to make a div looks like a popup (manipulating position absolute, width, height, adding a semi-transparent black background...).
Expect this give you a clue, there is a long time I worked with samsung tv's.