You could create a custom placeholder. Here’s a tutorial on creating custom placeholders: https://wp-events-plugin.com/documentation/tutorials/create-a-custom-placeholder-for-event-formatting/
If your ACF field is called “flyerfile” then the following code would create the #_FLYERLINK placeholder.
add_filter('em_event_output_placeholder','my_em_placeholders',10, 2);
function my_em_placeholders($replace, $EM_Event, $result){
if( $result == '#_FLYERLINK' ){
$replace = '<a href="'. get_field("flyerfile", $EM_Event->post_id, false) . '">Event Flyer</a>';
}
return $replace;
}
You can add the #_FLYERLINK to the event list format by going to Events Manger settings then in the Formatting tab enable “Advance Mode” and “Super Advance Mode” then in the Events section you can add the placeholder to the default events list format.