functions.php

<?php

/**
 * ACF Options Page 
 *
 */
function ea_acf_options_page() {
    if ( function_exists( 'acf_add_options_sub_page' ) ){
 		 acf_add_options_sub_page( array(
			'title'      => 'CPT Settings',
			'parent'     => 'edit.php?post_type=CPT_slug',
			'capability' => 'manage_options'
		) );
 	}
}
add_action( 'init', 'ea_acf_options_page' );