Tips on Customizing Coming Soon & Maintenance Mode Page

How to Hide the "Nifty Options" Admin Menu

function plt_hide_nifty_coming_soon_and_under_construction_page_menus() {
	//Hide the "Nifty Options" menu.
	remove_menu_page('niftycs-options');
}

add_action('admin_menu', 'plt_hide_nifty_coming_soon_and_under_construction_page_menus', 101);

Where do I put this code?

How to Hide the "Get a WP 301 Redirects PRO license for FREE $158" Dashboard Widget

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

	//Remove the "Get a WP 301 Redirects PRO license for FREE $158" widget.
	remove_meta_box('wp301promo_widget', 'dashboard', 'side');
}

add_action('wp_dashboard_setup', 'plt_hide_nifty_coming_soon_and_under_construction_page_dashboard_widgets', 20);