You can't view them until they've been downloaded. You can view what's being downloaded. How depends on what's doing the downloads - Samsung Internet? Play?
Canceling depends on which one you're using too. You can't cancel a download from Play. On Internet, it depends on the site - some keep a cancel button on screen during the download, some don't. If you don't want a download, and can't cancel it, just delete it after it finishes.