Jesus christ, would it be that hard just to make it yourself?
The first step would be to open the trigger editor, and manage your map's variables. Create a Bolean and call it HeroAlreadyPicked or somthing. Dont forget to check the array box, and type 12. Next, you have to understand the trigger. In the If/Then/Else part, if the condition in the If spot is satisfied, then the actions in the Then spot will run, but if the condition isn't satisfied in the If spot, then the actions in the Else section will run. In this case, the condition in the If spot is the variable you made. The trigger asks the computer if that variable is true or false. If it is true, then the actions in the Then spot will run, thereby removing the sold hero and creating a message to that player. But if the variable is false, the the actions in the Else spot will run. The actions in that spot tell to move the sold hero to the center of a region, pan the camera of the buying player to the center of that region, select the sold unit, and set the variable in the If spot to true. That way, if the same player tries to buy another hero, it will be removed, and the player will get a message saying that he cant have 2 heros. I hope this helps.
Tavern Hero Chosen
Events
Unit - A unit Sells a unit
Conditions
Actions
Game - Display to (All players) the text: You already chose a...
Set Herochosenbyplayer[(Player number of (Owner of (Sold unit)))] = True
Player Group - Pick every player in (All players) and do (Actions)
Player - Make (Unit-type of (Sold unit)) Unavailable for training/construction by (Picked player)
Camera - Pan camera for (Owner of (Sold unit)) to (Center of HeroSpawn <gen>) over 1.00 seconds
Selection - Clear selection for (Owner of (Sold unit))
