Noob Questions: Triggers

Ok, pretty easy questions.

How do I make it so if a player is choosing a hero, that only one person can choose that hero? Like unit enters region, and then have it so that hero cannot be chosen again? A full trigger would help a lot.

Also, how do I make a trigger so that when a player leaves it says like "Playername has left the game" ? A full trigger would help a lot.

Thanks,

Dark_Army

i can answer the first bit for you...

make all heros owned by player 12 (comp)
just have it so that if a unit enters region infrount of hero the you change that hero to owner of triggering unit and move to start the turn off trigger

say one of your herros is called warrior

--event--
unit enters region infront of "warrior"

--action--
change owner of warrior to owner of triggering unit
move unit instantly to start
turn off this trigger

i think thats right (dont have editor open rite now but should work

1.
Event-unit enters region
Action:
-trigger-turn this trig off
-change owner of hero to owner of triggering unit

2.
Event-periodic
Condit-player has left
Action
-game-show message to all players (player name+text)