Here is my tutorial that I made. I hope this helps:
Here is a trigger tutorial that is covering some basic information.
Doing a bridge that brokes when you go near it:
First do a bridge.( A simple rectangle brush) Left click on it and make it Func_breakable.(press "n")
Give it a key: targetname and value: bridge1(Can be word you want to call it!) Then give key: material and give value: x(I mean, any material you want, check the material list from the func_breakable. Press "n" and scroll the grey box to the bottom and you see the materials!.)
Then do a brush wich triggers the bridge. Place it where you want it to trigger the bridge. Texture it with system/trigger texture. Make it a trigger_once.(Remember the left click?) Give it key: target and value: bridge1. (the value should be the same as the bridge has!) Check the "Player only" thing.(Because we don't want tany NPC trigger it!) Now save and compile. When you go to the place where you put the trigger, the bridge collapses!(The trigger is invinciple of cource in tha game!)
When you go to a room, behind you spawns storm troopers!:
Do a trigger_once, (look above!) and texture it with trigger texture.
Give it a key: target and a value: troops
Check the player only!
Do few troopers, give each a key: targetname and value: troops
Save and compile.
Test it and when you go to the trigger, the troopers will spawn behind you!
Killing triggers(Like when you fall off a ledge or touch a electrical thing...):
First do a the place you want the player/npc to fall off. You could do the some kind of a bridge. Do a the place where the player/npc will fall
Then fill the area of the place where your guy falls in by doing a brush with "trigger" texture in it. REMEMBER! Put the trigger below the bridge!
Make it a trigger_hurt. Press "n" and give it a key: dmg and a value: 1000. Then check the falling.
Save and compile. When you enter the area where the trigger is, you will fall to down and die! Now I explain this trigger_hurt how does it works:
When ever kyle or any npc will touch this brush, it damages the guy.
To set the damage it does, give it a key: dmg and give it a value: x(I mean, put any value of damage to here you want it to inflict!)
The "player only" makes so that only kyle takes damage fromt his trigger.
The "No_protection" makes so that nothing stops the damage.
The "Silent" supresses sounds from the damage.
The "Lock cam" Locks the camera to one place and doesn't follow kyle to where he falls.
The "falling" makes npc/kyle to fall down and playes the falling scream.
The "electrical" makes npc/kyle take electrical damage!
The "NPc_only" makes the trigger to only hurt others than kyle.
Rules:
Give a to a trigger key: target and any value, the makeany entity and give it the same value and key:targetname. the trigger triggers the entity!
You can use a trigger multiple to make
There 10 kinds of people in the world: Those who understand binary arithmetics, and those who don't.
