Hello,
The functionality that you mentioned (getting a zoomable lightbox when you click a picture) is achieved by using the native WordPress [gallery] shortcode.
Here is how it works under the bonnet:
The theme overrides the default html that is generated by WP for the [gallery] shortcode. This is done by the mauer_gallery() function contained in the functions.php file of the theme. This function creates the markup for the PhotoSwipe library. This library, in turn, generates the lightbox.
By the code you posted I’m assuming you are trying to do that in a template file. So what you want to do is execute the shortcode the php way:
<?php echo do_shortcode('[gallery ids="179,180,181,182,183"]'); ?>
You can have one or more ids in the code above.
However I would also consider a solution where you don’t attach images through ACF and just use the native WP gallery (as in the demo content). I believe that can turn out to be much more convenient.