[Trigger] Simple gui need help

[Shanghai]

• Buy hero
  • Events
    • Unit - A unit Sells a unit
  • Conditions
    • ((Sold unit) is A Hero) Equal to True
  • Actions
    • Player - Make Footman Unavailable for training/construction by (Random player from (All players))

how i do this.

I want when my building = tavern sells this hero n one else ca be able to buy him build? how i do this can u show me the triggers how it gona be :S

 

[doom_sheep]

pick every player in player group - all players
make hero unavailable for training/construction by picked player