HCI documentation failed to mention it's not a Product but a (free) Tool so many - including myself - failed to find it by searching for it in Products. I submitted a bug report for documentation. The link by SpindleNinja above is where the tool can be currently downloaded.
I suggest to contact NetApp Support so that they can figure this out (and maybe give you access to download before the problem is fixed) - unfortunately those of us not from NetApp Support don't have a way to find out where the problem is.