How to Hide Booking Activities Admin Menus

function plt_hide_booking_activities_menus() {
	//Hide "Booking Activities".
	remove_menu_page('booking-activities');
	//Hide "Booking Activities → Home".
	remove_submenu_page('booking-activities', 'booking-activities');
	//Hide "Booking Activities → Calendar editor".
	remove_submenu_page('booking-activities', 'bookacti_calendars');
	//Hide "Booking Activities → Booking forms".
	remove_submenu_page('booking-activities', 'bookacti_forms');
	//Hide "Booking Activities → Bookings".
	remove_submenu_page('booking-activities', 'bookacti_bookings');
	//Hide "Booking Activities → Settings".
	remove_submenu_page('booking-activities', 'bookacti_settings');
}

add_action('admin_menu', 'plt_hide_booking_activities_menus', 21);

Where do I put this code?