Hi longvu76
No need to install any other extension, here is code of this module in our demo site, kindly check again:
<div id="myCarousel" class="carousel slide">
<!-- Carousel items -->
<div class="carousel-inner">
<div class="active item">
<div class="testimonial style-2 text-left">
<span class="author-img"><img src="images/demo/other/mark.jpg" alt="Avatar"/></span>
<h4>From just an idea to realization - Mark Lee, StackIdeas.com</h4>
<p class="testimonial-text">Glad to see this one see the light of the day, current Joomla! default templates have been topic of discussion for late and JA Simpli should help to fill the gap. JoomlArt, For the love of Joomla, you guys now got to roll out a admin template too.</p>
</div>
</div>
<div class="item">
<div class="testimonial style-2 text-left">
<span class="author-img"><img src="images/demo/other/parth.jpg" alt="Avatar"/></span>
<h4>Parth lawate, TechJoomla</h4>
<p class="testimonial-text">This is a simply fantastic effort ! In a time where templates without any special 'frameworks' are not thought of anymore, you have proven yet again that there is plenty of room to innovate. Now that you have shown what you can do with the Joomla frontend, how about a breath of fresh air for the Joomla admin?</p>
</div>
</div>
</div>
<ol class="carousel-indicators">
<li data-target="#myCarousel" data-slide-to="0" class="active"></li>
<li data-target="#myCarousel" data-slide-to="1"></li>
</ol>
</div>