The software works as a cloud manager & file manager for your files. If the file you try to download is hosted on the cloud service, then you have to connect to that service and then download it through its built-in download module. I've accessed the only page available at the App Store, but there are no instructions on how to properly obtain that file except the solution I've posted here.
Unfortunately, the support link that is provided on the page is not working at all. Also, for email services, I don't recommend using a download manager because in most of the cases you will have the full file, but there might be a possibility that the final package to be corrupted.