Randomized featured image in homepage (Supreme Directory)

Hi,

I’ve been trying out Supreme Directory and I have been enjoying it so far. However, I’ve been trying to implement a randomized homepage image feature using the Dynamic Featured Image (https://github.com/ankitpokhrel/Dynamic-Featured-Image) plugin and thus far I haven’t succeeded. I assumed editing the index.php file would be the way to go, specifically the section below, but it doesn’t seem to have any effect.

 <div class="featured-area">
        <div class="featured-img" <?php
        $page_for_posts = get_option('page_for_posts');
        if (has_post_thumbnail($page_for_posts)) { // check if the post has a Post Thumbnail assigned to it.
            $full_image_url = wp_get_attachment_image_src(get_post_thumbnail_id($page_for_posts), 'full');
        }else{
            $full_image_url[0] = SD_DEFAULT_FEATURED_IMAGE;
        }
            ?> style="background-image: url('<?php echo esc_url($full_image_url[0]); ?>');" <?php
        ?>>
        </div>

Can you point me towards the files to edit to make this change? Thanks in advance, Diogo Carneiro