Ok, as requested.
Create an ACF field.
Add a repeater field.
Inside the repeater, add a text field with name title.
Inside the repeater, add an URL field with name link.
$menu_items = get_field( 'repeater_field' )
if ( $menu_items ) {
echo '<ul>';
foreach( $menu_items as $item ) {
echo '<li><a href="https://wordpress.stackexchange.com/questions/298949/{{ item.link }}">{{ item.title }}</a></li>';
}
echo '</ul>';
}
You can then link to any sub-pages you have created.