What's the correct syntax for quotes within a php statement?

Hi there,

Hacking my way through PHP – most of the time okay but cannot work this out so thought I’d ask a far greater power!

I’m trying to echo a field from setup using the advanced custom fields plugin. The query’s working fine on another template but I can’t get the echo to work and I’m sure it’s to do with my ‘newbie’ status.

The code I’m getting blurry eyed over is ,,,

<?php $args = array(
    'numberposts' => 3,
    'offset' => 0,
    'orderby' => 'post_date',
    'order' => 'DESC',
    'post_type' => 'publications',
    'meta_query' => array(
            array(
                    'key' => 'project',
                    'value' => $post->ID,
            )
    )
);
$posts_array = get_posts( $args );
if( $posts_array ) {
    foreach( $posts_array as $related ) {
		echo '<a href="' . $related->guid . '">' . linked words . '</a>';
    }
}

I want it to echo a field from the related post rather than the guid:

echo '<a href="<?php the_field('field_name'); ?>">' . linked words . '</a>';

But the ” and the ‘ syntax isn’t correct – the ‘ ‘ around the field_name stuffs up the code.

There’s probably an easy, easy answer but stuffed it I can work it out.

Any one got any ideas?

Thanks in advance