Usage Custom Field in custom post query

Custom post default

<?php $job_link= get_post_meta($post->ID, 'job_instructions', true); ?>
<?php echo $job_link; ?>


Custom post if exists

<?php if($job_link) :  ?>
    <a href="<?php echo $job_link; ?>" class="job_pdf">Download Instructions</a>
<?php endif; ?>



Custom post dynamic

<?php if ( $job_link ) : ?>
    <a href="<?php echo $job_link; ?>" class="job_pdf">Download Instructions</a>
<?php else : ?>
    <p style="float:right">no job instructions available</p>
<?php endif; ?>