[Theme Horse Support Team]

hi kelsey,

We are using action hook. This all file is located inside your theme folder -> library -> structure -> content-extension.php
All pages are controlled from this file.

if ( ! function_exists( 'cleanretina_theloop_for_archive' ) ) :
/**
 * Fuction to show the archive loop content.
 */
function cleanretina_theloop_for_archive() {
	global $post;
	global $cleanretina_theme_options_settings;
	$options = $cleanretina_theme_options_settings;

	if( have_posts() ) {
		while( have_posts() ) {
			the_post();

			do_action( 'cleanretina_before_post' );
?>
	<section id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
		<article class="clearfix">

			<?php do_action( 'cleanretina_before_post_header' ); ?>

			<header class="entry-header">
    			<h2 class="entry-title">
    				<a href="<?php the_permalink(); ?>" title="<?php the_title_attribute();?>"><?php the_title();?></a>
    			</h2><!-- .entry-title -->
    			<?php if (get_the_author() !=''){?>
                        	<div class="entry-meta">
					<span class="by-author vcard author"><span class="fn"><?php _e( 'By', 'cleanretina' ); ?> <a href="<?php echo get_author_posts_url( get_the_author_meta( 'ID' ) ); ?>"><?php the_author(); ?></a></span></span>
             	<span class="date updated"><a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( get_the_time() ); ?>"><?php the_time( get_option( 'date_format' ) ); ?></a></span>
             	<?php if( has_category() ) { ?>
             		<span class="category"><?php the_category(', '); ?></span> 
             	<?php } ?>
             	<?php if ( comments_open() ) { ?>
             		<span class="comments"><?php comments_popup_link( __( 'No Comments', 'cleanretina' ), __( '1 Comment', 'cleanretina' ), __( '% Comments', 'cleanretina' ), '', __( 'Comments Off', 'cleanretina' ) ); ?></span>
             	<?php } ?>
         	</div><!-- .entry-meta -->
         	<?php } ?>
        		</header>

  			<?php do_action( 'cleanretina_after_post_header' ); ?>

  			<?php do_action( 'cleanretina_before_post_content' ); ?>

  			<?php
  			if( 'excerpt_display_one' == $options[ 'blog_display_type' ] || 'excerpt_display_two' == $options[ 'blog_display_type' ] ) {
	  			if( 'excerpt_display_one' == $options[ 'blog_display_type' ] ) {
	  				$featured_image_type = 'featured';
	  			}
	  			else {
	  				$featured_image_type = 'featured-medium';
	  			}

				if( has_post_thumbnail() ) {
					$image = '';        			
		     		$title_attribute = apply_filters( 'the_title', get_the_title( $post->ID ) );
		     		$image .= '<figure class="post-featured-image">';
	     			$image .= '<a href="' . get_permalink() . '" title="'.the_title_attribute( 'echo=0' ).'">';
	     			$image .= get_the_post_thumbnail( $post->ID, $featured_image_type, array( 'title' => esc_attr( $title_attribute ), 'alt' => esc_attr( $title_attribute ) ) ).'</a>';
	     			$image .= '</figure>';

		  			echo $image;
		  		}
	  			?>
	  			<?php if (get_the_author() !=''){?>
	  			<div class="entry-content clearfix">
	    			<?php 
	    				the_excerpt();
	    				echo '<a class="readmore" href="' . get_permalink() . '" title="'.the_title( '', '', false ).'">'.$options[ 'post_excerpt_more_text' ].'</a>'; 
	    			?>
	  			</div><!-- .entry-content --> 
	  			<?php } else{
			the_content();	
				} ?>

		  		<?php
			  	}
			  	else {
			  	?>
			  		<div class="entry-content clearfix">
			  			<?php
			  			the_content( $options[ 'post_excerpt_more_text' ] );
			  			wp_link_pages( array( 
							'before'            => '<div style="clear: both;"></div><div class="pagination clearfix">'.__( 'Pages:', 'cleanretina' ),
							'after'             => '</div>',
							'link_before'       => '<span>',
							'link_after'        => '</span>',
							'pagelink'          => '%',
							'echo'              => 1 
	               ) ); 
			  			?>
			  		</div><!-- .entry-content -->
			  	<?php
		  	}
		  	?>

  			<?php do_action( 'cleanretina_after_post_content' ); ?>

		</article>
	</section>
	<hr/>
<?php
			do_action( 'cleanretina_after_post' );

		}
	}
	else {
		?>
		<h1 class="entry-title"><?php _e( 'No Posts Found.', 'cleanretina' ); ?></h1>
      <?php
   }
}
endif;

This argument you need to pass inside this function. View this link
http://codex.wordpress.org/Function_Reference/get_categories

You need to customise the code inside this function. If you are still unable then you may hire a developer to fix the issue.

Thank you!