You would need to do a query of the posts of that type, getting them all 'posts_per_page' => -1, and order them by whatever you want to order them by. You can return just a list of IDs by setting 'feilds' => 'ids', Then you can use this returned array of IDs to order your posts. To do this you set 'post__in' => $return_from_first_query, and 'orderby' => 'post__in'.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users