How to make images in slick replaceable with ACF gallery + WP?

Question

Images

<div id="slider" class="content_slider" style="position: absolute;">
                          <?php 
      $images = get_field('gallery');

                    if( $images ): ?>
           <?php foreach( $images as $image ): ?>
             <img src="<?php echo $image['url']; ?>" alt="<?php echo $image['alt']; ?>">
           <?php endforeach; ?>
                    <?php endif; ?>
              </div>

Screenshot

It is required to make it so that if the administrator uploads new images to the gallery, then he selects certain photos in the setting.
Very weak in WP, please explain...
Above is the code, all I could. The images never showed up.