Tips on Customizing WordPress Simple Shopping Cart

How to Hide WP Simple Shopping Cart Admin Menus

function plt_hide_wordpress_simple_paypal_shopping_cart_menus() {
	//Hide "Settings → WP Simple Shopping Cart".
	remove_submenu_page('options-general.php', 'wordpress-paypal-shopping-cart');

	//Hide "Cart Orders".
	remove_menu_page('edit.php?post_type=wpsc_cart_orders');
	//Hide "Cart Orders → Cart Orders".
	remove_submenu_page('edit.php?post_type=wpsc_cart_orders', 'edit.php?post_type=wpsc_cart_orders');
	//Hide "Cart Orders → Add New Order".
	remove_submenu_page('edit.php?post_type=wpsc_cart_orders', 'post-new.php?post_type=wpsc_cart_orders');

	//Hide "Simple Cart".
	remove_menu_page('wspsc-menu-main');
	//Hide "Simple Cart → Settings".
	remove_submenu_page('wspsc-menu-main', 'wspsc-menu-main');
	//Hide "Simple Cart → Coupons".
	remove_submenu_page('wspsc-menu-main', 'wspsc-discounts');
	//Hide "Simple Cart → Tools".
	remove_submenu_page('wspsc-menu-main', 'wspsc-tools');
	//Hide "Simple Cart → Add-ons".
	remove_submenu_page('wspsc-menu-main', 'wspsc-addons');
}

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

Where do I put this code?

How to Hide WP Simple Shopping Cart Meta Boxes

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

	//Hide the "Order Review" meta box.
	remove_meta_box('order_review_meta_box', $screen->id, 'normal');
	//Hide the "Order Actions" meta box.
	remove_meta_box('order_actions_meta_box', $screen->id, 'side');
}

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