How to add new column on a custom post type in WordPress back-office?

       // Add the custom columns
        add_filter( 'manage_ogpqrcode_posts_columns',  'set_custom_columns' );
	function set_custom_columns($columns) {
	    unset( $columns['author'] );
	    $columns['ref_name'] = __( 'Ref', 'your_text_domain' );
	    $columns['qr_code'] = __( 'QR Code', 'your_text_domain' );

	    return $columns;
	}

	// Add the data to the custom columns 
        add_action( 'manage_ogpqrcode_posts_custom_column' ,  'custom_column', 10, 2 );
	function custom_column( $column, $post_id ) {

		$product_ref = get_field('ref_produit', $post_id);
		$post_slug = get_post_field( 'post_name', $post_id );


		$imgfilename = plugin_dir_url( __FILE__ ). "qrcode-img/".$product_ref."-".$post_slug.".png";
	
	    switch ( $column ) {

	        case 'ref_name' :

	        	echo $product_ref;
	            break;

	        case 'qr_code' :
	           	
	           	echo '<a href="'.$imgfilename.'" target="_blank">Télécharger</a>';
	       		//echo $imgfilename;
	            break;

	    }
	    
	}