How to Hide Easy Table Booking Admin Menus

function plt_hide_easy_table_booking_menus() {
	//Hide "Easy Table Booking".
	remove_menu_page('my-menu');
	//Hide "Easy Table Booking → Bookings".
	remove_submenu_page('my-menu', 'tbl-bookings');
	//Hide "Easy Table Booking → Add Table".
	remove_submenu_page('my-menu', 'tbl-addtable');
	//Hide "Easy Table Booking → Table List".
	remove_submenu_page('my-menu', 'tbl-list');
	//Hide "Easy Table Booking → Settings".
	remove_submenu_page('my-menu', 'tbl-settings');
}

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

Where do I put this code?