How to make navPreNext button visible in layer slider responsive?

How to make navPreNext button visible in layer slider responsive?

I am trying to using layer slider responsive provide by js . IN short I am
using layer slider and unable to show next and prev button on the slider.
Below is my code
<script type="text/javascript">
// jQuery $('document').ready(); function
// Calling LayerSlider on your selected element after the document loaded
$('document').ready(function(){
$('#layerslider').layerSlider({
responsive: false,
autoStart : true,
navPrevNext: true,
skin : 'default'
});
});
</script>
HTML
<div id="layerslider" style="width: 1404px; height: 404px;">
<div class="ls-layer">
<img class="ls-bg" src="../img/image-slider-1(small).png"
alt="layer1-background">
</div>
</div>