Amazon S3 - Select user's folders for uploading

There are few users with their own folders on my storage and I am trying to use Amazon S3 as a cloud backup system. I enabled it in my WD Admin panel.
The problem is that i can’t select user’s folders when i create task for cloud backup. I see only public folders.
What can i do with it? How can i backup user’s folders?

What My Cloud device do you have? What specific setting did you enable?

The single drive My Cloud units (AFAIK) do not support Amazon S3 and there is no option in the My Cloud Dashboard that mentions Amazon S3.

If you are using an EX2, EX4, EX Series or DL Series, see their respective subsections in the Network attached Storage section.

I am not sure about exact name of my Storage but it’s menu looks like this - you can see Amazon button in the right corner.