Advanced Custom Fields - Theme options register and sub-pages

acf-theme-options.php

/*
* Register Theme Option pages
*/
if( function_exists('acf_add_options_page') ) {
  acf_add_options_page(array(
    'page_title'    => 'Theme Options',
    'menu_title'    => 'Theme Options',
    'menu_slug'     => 'theme-options',
    'capability'    => 'edit_posts',
    'redirect'      => false
  ));
  
  acf_add_options_sub_page(array(
    'page_title'    => 'Contact Details',
    'parent_slug'   => 'theme-options'
  ));
  
  acf_add_options_sub_page(array(
    'page_title'    => 'Blog Options',
    'parent_slug'   => 'theme-options'
  ));
}