Edit in JSFiddle

<div id="carouselExampleIndicators" class="carousel slide">
  <ol class="carousel-indicators">
    <li data-target="#carouselExampleIndicators" data-slide-to="0" class="active"></li>
    <li data-target="#carouselExampleIndicators" data-slide-to="1"></li>
    <li data-target="#carouselExampleIndicators" data-slide-to="2"></li>
  </ol>
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="First slide">
            <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="First slide">
      <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="First slide">
    </div>
    <div class="carousel-item">
      <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="Second slide">
            <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="First slide">
      <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="First slide">
    </div>
    <div class="carousel-item">
      <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="Third slide">
            <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="First slide">
      <img src="https://image.shutterstock.com/image-vector/light-bulb-line-icon-vector-260nw-416374336.jpg" alt="First slide">
    </div>
  </div>
  <a class="carousel-control-prev" href="#carouselExampleIndicators" role="button" data-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="sr-only">Previous</span>
  </a>
  <a class="carousel-control-next" href="#carouselExampleIndicators" role="button" data-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="sr-only">Next</span>
  </a>
</div>
.carousel-item {
}
.carousel-item img {
  width: 31%;
  font-size: 0;
  display: inline-block;
}
.carousel-indicators li,
.carousel-control-prev,
.carousel-control-next {
  border: 1px solid grey;
}