<div class="swiper-container">
 <div class="swiper-slides"></div>
</div>
<div class="swiper-button-prev-unique"></div>
<div class="swiper-button-next-unique"></div>

let carousel = new Swiper('.swiper-container', {
  navigation: {
    nextEl: '.swiper-button-next-unique',
    prevEl: '.swiper-button-prev-unique'
  }
});