Since the Tableau Catalog is part of 2019.3, it is still beta code and not released. Understand that sometimes with beta code a feature may slip if some issue is found during the beta testing. All beta questions should be posted to the beta pre-release site found here: http://prerelease.tableau.com
I would suggest you look at the fairly extensive notes about Tableau Catalog posted in that site here: https://prerelease.tableau.com/project/article/default.html?cap=90a86e6542194b2c950aa3dc413c7399&arttypeid=aeb9b498f85940b5a98aabb20b492b96
There is also a FAQ section where you can post beta questions and the beta team will answer those questions there.
It's just too early to post videos or demos or feature lists until beta is released to production, otherwise things could easily change and the video would be wrong. Hope you understand.
We hope to be releasing 2019.3 real soon........in Q3/2019...not that far away.... :-)