var slider = $('.bxslider').bxSlider({
  mode: 'fade'
});

$('#slider-next').click(function(){
  slider.goToNextSlide();
  return false;
});

$('#slider-count').click(function(){
  var count = slider.getSlideCount();
  alert('Slide count: ' + count);
  return false;
});

<div class="bxslider">
  <div><img src="http://placehold.it/900x200&text=Slide 1" /></div>
  <div><img src="http://placehold.it/900x200&text=Slide 2" /></div>
  <div><img src="http://placehold.it/900x200&text=Slide 3" /></div>
</div>

<p><a href="" id="slider-next">Click me to go to the next slide</a><br />
<a href="" id="slider-count">Click me to see the total slide count</a></p>