Xin, it really is too bad they don't post the workbooks with the videos. I glanced at the viz you're talking about and he has several table calculations working, so the steps for that particular viz are going to be dense indeed. Without the workbook it's tough to guess exactly how he did it.
I'm attaching workbook of dozens of sample vizzes put together by a team of Tableau employees. This would be a excellent workbook to use to improve your Tableau knowledge. When you can recreate all these, you'll be well on your way to having mastered Tableau.
FYI: On the "More Visualization I" tab, the map in the lower right uses a quick filter to filter to a radius. Not the same, but a start in that direction.
TeamGeiger8.0.twbx 23.3 MB
Thank you for sharing the learning vizzes. I found it difficult to get enough training materials and you just saved me out of that. Though I haven't started learning your vizzes and it would help me improve a lot for sure. Really Great Help.