Tips on Customizing Advanced Testimonial

How to Hide Advanced Testimonial Admin Menus

function plt_hide_advanced_testimonial_menus() {
	//Hide "Testimonials".
	remove_menu_page('edit.php?post_type=testimonial');
	//Hide "Testimonials → All Testimonials".
	remove_submenu_page('edit.php?post_type=testimonial', 'edit.php?post_type=testimonial');
	//Hide "Testimonials → Add New Testimonial".
	remove_submenu_page('edit.php?post_type=testimonial', 'post-new.php?post_type=testimonial');
	//Hide "Testimonials → Groups".
	remove_submenu_page('edit.php?post_type=testimonial', 'edit-tags.php?taxonomy=testimonial_group&post_type=testimonial');
	//Hide "Testimonials → Settings".
	remove_submenu_page('edit.php?post_type=testimonial', 'advanced-testimonial-settings');
	//Hide "Testimonials → Demo Library".
	remove_submenu_page('edit.php?post_type=testimonial', 'advanced-testimonial-demos');
}

add_action('admin_menu', 'plt_hide_advanced_testimonial_menus', 11);

Where do I put this code?

How to Hide the "Testimonial Details" Meta Box

function plt_hide_advanced_testimonial_metaboxes() {
	$screen = get_current_screen();
	if ( !$screen ) {
		return;
	}

	//Hide the "Testimonial Details" meta box.
	remove_meta_box('advanced-testimonial-details', $screen->id, 'normal');
}

add_action('add_meta_boxes', 'plt_hide_advanced_testimonial_metaboxes', 20);