Select a page (if don't, not display) – Options Framework Plugin

Wrap your whole query inside of_get_option(‘test’).

E.g.:

<?php if ( of_get_option('test', false ) ) { ?>
<div>
   <?php $recent = new WP_Query('page_id='.of_get_option('test')); while($recent->have_posts()) : $recent->the_post();?>
   <h3><?php the_title(); ?></h3>
   <?php the_excerpt(); ?>
   <?php endwhile; ?>
   <a href="<?php the_permalink() ?>" rel="bookmark">Learn More</a>
</div>
<?php } ?>

How could you edit this if you wanted to display pages OR posts?

You would use an else if statement:

<?php
	$opid1 = of_get_option('myoptionsid1');
	$opid2 = of_get_option('myoptionsid2'); /* And so on to call more optionfields*/

?>
<?php
if (empty($opid1)) { ?>
  /* Choise what to do if field $opid1 IS empty */
<?php echo ''; ?> /* Displays whatever is between the '', in this case nothing */

<?php } else if { ?>
/* First choise what to do if field $opid1 NOT empty */
<a href="<?php echo ($opid1); ?>"> /* myoptionsid1 are in this case an URL to wherever i want to link*/
<img src="<?php echo ($opid2); ?>" /> /* myoptionsid2 are in this case an URL to an image*/
</a>

<?php } else if { ?>
/* Second choise what to do if field $opid1 NOT empty. And so on... */

<?php } else { ?>
/* Last choise what to do if field $opid1 NOT empty */

<?php };
?>

For more if else statements: https://codex.www.ads-software.com/Conditional_Tags