Download a file from within a zoho creator widget

Download a file from within a zoho creator widget

I have a widget running in Zoho Creator , it displays uploaded documents in a table file, and I have added a download link in the view. ( The widget is created with html, css and javascript).
I do not succeed in getting the download working. Do I have to use the download functionality described here:
https://www.zoho.com/creator/help/api/v2.1/download-file.html

And if so, how to get a correct access token?
The process is not clear to me. Has someone an example?