If you checked that link .The attached workbook down there the country flag and country name is not correct.
The process will be the same. You just need to map countries and flags appropriately. Anyway it's a manual process.
Please Find the below attachment marked as Correct or Helpful if it is Working.
1) Create A Folder "Flag"
2)Download and Save All images in tha floder i.e. "Flag" folder.
3)Copy "Flag" Folder and Paste it into "My Tableau Repository\Shapes\Flags"
4)Go to you Tableau Workbook->Marks->Select Shape->Select Shape Palette "Flag"
5)Select Flags as per Country->Apply->Ok
6)Images add into workbook.
Amar D. Savale
Solution_v10.2.twbx 136.0 KB