How to list selected items which are in a loop into a another question question which is not in a loop

If you downloaded the file saved as xml file it should work because I tested it. What error do you encounter? Any message, screenshot etc?

@Grzesiek2010 I have also tried using ODK online and it is not working

You don't need to convert that file it's not xls but already converted xml so it's ready and you can upload it to you server.