To restore files, sign into your iCloud account through the browser, and go to Settings → Data & Security. You can then browse a list of files in the Recover Documents tab. Files are removed from Recover Documents after 30 days, so don’t wait long to restore something.
A useful tip to restore wrongly deleted files in iCloud. By the way, I paid the extra bucks to extend the period of my Dropbox storing all deleted files to 1 year.