Kudos to this team: I was interested in this and began the process - needed to sign up for a Rockset account to follow this tutorial; ran into an issue uploading my collection - and the fact that I needed to get my free account activated:

They replied to my request for access immediately, got me up and running, had a support eng on a Slack channel in minutes and a personal apology from the CEO for the error.

Great fricken customer service!