Search button for the win.
Try reading some tutorials, because if you are asking how-to-do-something in here, you've got to understand fully the object and the terrain editor and also some basic things like what's a trigger, event, condition, action, variable, gameplay interface/constants and how to add shown triggers in your map. If you don't know any of these, you aren't grown enough to understand what has been given to you as answers. Cheers and good luck.
TriggerHappy187, you got to have nerves of steel. But thou shalt not use Lord's name in vain =P