How to Hide Ninja Tables Admin Menus

function plt_hide_ninja_tables_menus() {
	//Hide "Ninja Tables".
	remove_menu_page('ninja_tables');
	//Hide "Ninja Tables → Tables".
	remove_submenu_page('ninja_tables', 'admin.php?page=ninja_tables#/');
	//Hide "Ninja Tables → Import".
	remove_submenu_page('ninja_tables', 'admin.php?page=ninja_tables#/tools');
	//Hide "Ninja Tables → Tools".
	remove_submenu_page('ninja_tables', 'admin.php?page=ninja_tables#/tools');
	//Hide "Ninja Tables → Charts".
	remove_submenu_page('ninja_tables', 'admin.php?page=ninja_tables#/charts');
	//Hide "Ninja Tables → Get Pro".
	remove_submenu_page('ninja_tables', 'https://wpmanageninja.com/downloads/ninja-tables-pro-add-on/?utm_source=ninja-tables&utm_medium=wp&utm_campaign=wp_plugin&utm_term=upgrade_menu');
	//Hide "Ninja Tables → Help".
	remove_submenu_page('ninja_tables', 'admin.php?page=ninja_tables#/help');
}

add_action('admin_menu', 'plt_hide_ninja_tables_menus', 11);
Where do I put this code?