Tips on Customizing WP Book Manager

How to Hide WP Book Manager Admin Menus

function plt_hide_wp_book_manager_menus() {
	//Hide the "Book Manager" menu.
	remove_menu_page('edit.php?post_type=book');
	//Hide the "Book Manager → All Books" menu.
	remove_submenu_page('edit.php?post_type=book', 'edit.php?post_type=book');
	//Hide the "Book Manager → Add New Books" menu.
	remove_submenu_page('edit.php?post_type=book', 'post-new.php?post_type=book');
}

add_action('admin_menu', 'plt_hide_wp_book_manager_menus', 15);

Where do I put this code?

How to Hide the "Book Manager" Meta Box

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

	//Hide the "Book Manager" meta box.
	remove_meta_box('book_management', $screen->id, 'advanced');
}

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