You can create a gallery using the following structure:
<section class="large-section">
<div class="container-fluid isotope-grid-wrapper">
<div class="image-gallery isotope-grid image-gallery-4-columns">
<div class="grid-item">
<a href="assets/img/gallery/gallery-1.jpg" class="gallery-item item-inner">
<span class="image-overlay">
<i class="icofont-search"></i>
<img src="assets/img/gallery/gallery-1.jpg" alt="gallery-item-1" class="img-fluid">
</span>
</a>
</div>
</div>
</div>
</section>