How to Hide Ultimate Gutenberg - Custom Block Templates Admin Menus

function plt_hide_ultimate_gutenberg_menus() {
	//Hide "Ultimate Gutenberg".
	remove_menu_page('ultimate-gutenberg-info.php');
	//Hide "Ultimate Gutenberg → Ultimate Gutenberg".
	remove_submenu_page('ultimate-gutenberg-info.php', 'ultimate-gutenberg-info.php');
	//Hide "Ultimate Gutenberg → Affiliation".
	remove_submenu_page('ultimate-gutenberg-info.php', 'ultimate-gutenberg-info.php-affiliation');
	//Hide "Ultimate Gutenberg → Contact Us".
	remove_submenu_page('ultimate-gutenberg-info.php', 'ultimate-gutenberg-info.php-contact');
	//Hide "Ultimate Gutenberg → Upgrade".
	remove_submenu_page('ultimate-gutenberg-info.php', 'ultimate-gutenberg-info.php-pricing');
}

add_action('admin_menu', 'plt_hide_ultimate_gutenberg_menus', 1000000000);

Where do I put this code?