Hi @indian-outskirts
If you want to filter the search based on the custom field, you can take a look at this page: https://www.advancedcustomfields.com/resources/creating-wp-archive-custom-field-filter/.
That page is talking about archive pages, but the logic should be the same. You can set an attribute to the search URL and get it using the $_GET method. To query based on custom field, please take a look at this page: https://www.advancedcustomfields.com/resources/query-posts-custom-fields/.
I hope this helps 🙂
