How to lock camera after player chooses a unit?

okay in my map there player starts out adn needs to select a hero. after he/she chooses the hero and there hero spawns at a location how would i gte the camera to lock. keep in mind this is a bnet game. and try to give me it in trigger form...

The action Camera- lock camera target to unit will do it. You could tell it to lock onto a random unit in a small region where the unit spawns so it will lock onto whichever unit appears.
Note: Many people hate the locked camera mode, you may want to give people an option to disable it.

mostly likely you would want to store the picked unit in a unit array because many times im sure you will need to refer to the unit during the map, as the player picks set (varible)[player number] = to the the unit that was picked

then like myster mystery said, use Camera - Lock Camera to (Varible[Player Number])