You can download it here: https://www.moddb.com/games/battlefield-vietnam/addons/bfv-forcepack-platinum

After this make sure you download the patch: www.moddb.com/games/battlefield-vietnam/addons/bfv-forcepack-platinum-patcher

Before running the game make sure you check your levels' folder:
Battlefield Vietnam/Mods/BfVietnam/Archives/BfVietnam/Levels

These should work, then you can play the event on this server:
https://www.gametracker.com/server_info/158.69.118.94:15568/

Event starts: May 15, 2021 6PM GMT +2

See you on the battlefield soldier!

Regards,

agathyus