How to download the attached file to the quiz( https://www.screencast.com/t/kwWCsKm7 ), on the part of the admin
The quiz doesn't have an upload function as this is what the Assignment module is for.
However, a way around this would be to use an essay question and leave instructions for the student to upload their file as a link within the essay's text box. I.e. click on the "Link" button on Atto's toolbar and click "Browse repositories" > "Upload a file" to upload their file into the text box as a link.