How to Hide Truebooker - Appointment Booking and Scheduler System Admin Menus

function plt_hide_truebooker_appointment_booking_menus() {
	//Hide "Truebooker".
	remove_menu_page('truebooker');
	//Hide "Truebooker → Truebooker".
	remove_submenu_page('truebooker', 'truebooker');
	//Hide "Truebooker → Appointments".
	remove_submenu_page('truebooker', 'appointments');
	//Hide "Truebooker → Customers".
	remove_submenu_page('truebooker', 'customers');
	//Hide "Truebooker → Branch".
	remove_submenu_page('truebooker', 'truebooker_branch');
	//Hide "Truebooker → Departments".
	remove_submenu_page('truebooker', 'departments');
	//Hide "Truebooker → Services".
	remove_submenu_page('truebooker', 'services');
	//Hide "Truebooker → Categories".
	remove_submenu_page('truebooker', 'categories');
	//Hide "Truebooker → Setting".
	remove_submenu_page('truebooker', 'setting');
	//Hide "Truebooker → FAQ".
	remove_submenu_page('truebooker', 'faq');
}

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

Where do I put this code?