How to Hide Post Meta Data Manager Admin Menus

function plt_hide_post_meta_data_manager_menus() {
	//Hide the "PMDM Settings" menu.
	remove_menu_page('pmdm-general-settings');
	//Hide the "PMDM Settings → PMDM Settings" menu.
	remove_submenu_page('pmdm-general-settings', 'pmdm-general-settings');
	//Hide the "PMDM Settings → Help" menu.
	remove_submenu_page('pmdm-general-settings', 'pmdm-help');
}

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

Where do I put this code?