I was able to duplicate the screens you showed above. You are, I assume, working in Excel online. There are a number of areas where the online version has less functionality than the full down-loaded version. This appears to be one of those limitations. I was only able to go so far in duplicating your situation since I do have it on my computer. However, I did not see any way to get from here to there unless you can open it in a local application on your computer. Notepad doesn't help as long as the file is still saved as an Excel file because it opens all of the programmatic info as well--not just the file info.
My best suggestion would be to download it to your computer and save on a flash drive that you could use on a computer with Excel installed to re-save then as .csv.
Hope this helps and you can figure this out.
Rich~M