Tips on Customizing Parcel Tracking

How to Hide Parcel Tracker Admin Menus

function plt_hide_parcel_tracker_menus() {
	//Hide "Packages".
	remove_menu_page('edit.php?post_type=patrack_package');
	//Hide "Packages → Packages".
	remove_submenu_page('edit.php?post_type=patrack_package', 'edit.php?post_type=patrack_package');
	//Hide "Packages → Add New Package".
	remove_submenu_page('edit.php?post_type=patrack_package', 'post-new.php?post_type=patrack_package');
	//Hide "Packages → Settings".
	remove_submenu_page('edit.php?post_type=patrack_package', 'patrack-settings');
}

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

Where do I put this code?

How to Hide the "Package Details" Meta Box

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

	//Hide the "Package Details" meta box.
	remove_meta_box('patrack_meta', $screen->id, 'normal');
}

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