I checked the site and it seems that the page is still members-only and which makes it non-searchable.
As mentioned in the video, if you want users to search the materials but still need to sign up, you can have a list of the materials on a public page and link to a members-only page for the list of files.
It can take some time for the page to be crawled; I was checking on my account and after publishing a few times and waiting for a few minutes, I was able to search the page.
The inverse would happen as well when the page could be searchable for a bit even if it’s members-only so it can take some time for the site to be crawled and indexed in the search results.