How to Hide Beaverlodge Maintenance Admin Menus

function plt_hide_beaverlodge_maintenance_menus() {
	//Hide the "Plugins → Install Plugins" menu.
	remove_submenu_page('plugins.php', 'tgmpa-install-plugins');
	//Hide the "Settings → Beaverlodge Maintenance" menu.
	remove_submenu_page('options-general.php', 'sw-maintenance-options');
}

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

Where do I put this code?