first you must understand the inferstructure or triggers. event condition action. it basically means when something happens (event) so long as whatever is true (condition) do something(action). you must also understand that whatever is in the tirggers will only work when applied to the map itself. so when you say "a unit to start in one place, go to anouther, kill the units there, and then do the whole thing again" you must know where the unit starts, what the unit is or who it belongs to, where it is going to kill units, how it is going to get there and where it is going to go back to.
you havent been very specific about the event or conditions or what is on the map.
however i can tell by what you are saying you need some regions. a region for the unit to start in and a region for the unit to go. if you do not know about regions yet, look at the tutorial or tinker about with world editor until you understand them.
here is an example, i have used the region "unit spawn" to show where your unit starts, and i have used the position of a specific enemy as where it will attack. as i said you were not specific about events or conditions so i have chosen 5 seconds after the game has started as the event and no conditions to keep things simple.
[trigger:1:56afc0c6fd]
Untitled Trigger 001
Events
Time - Elapsed game time is 5.00 seconds
Conditions
Actions
Unit - Create 1 Footman for Player 1 (Red) at (Center of Unit Spawn <gen>) facing Default building facing degrees
Wait 0.10 seconds
Unit - Order (Last created unit) to Attack Spell Breaker 0000 <gen>
[/trigger:1:56afc0c6fd]
so here we have a very simple trigger which spawns a unit at the center of the region called unit spawn and then it attacks a already existing unit on the map which is a spell breaker. WE (world editor) is very picky about certain things, timing is one of them. if you were to run this trigger without the "Wait 0.10 seconds" action there its possible that the unit would not receive this order because the trigger has actually finished before the game could spawn the unit. the game is fast but triggers are faster. because the wait is so short you wont notice it.
the next stage is to have the unit move back to the "unit spawn" region after the enemy is dead. this is where conditions are involved because the game needs to know the enemy unit is dead. there are two ways of doing this, you can either "Wait until (((Targeted unit) is dead) Equal to True), checking every 0.10 seconds" or you can make a brand new trigger for it. generally we use the latter because checking every 0.10 seconds tends to cause lag, especially if there are alot of other triggers going on at the same time.
in this trigger your event will be the enemy units death. to make sure the enemy unit is dead we must have conditions to make sure the dying unit is and enemy of player 1 (red) and is the spell breaker.
[trigger:1:56afc0c6fd]
Untitled Trigger 002
Events
Unit - A unit Dies
Conditions
((Owner of (Triggering unit)) is an enemy of Player 1 (Red)) Equal to True
(Triggering unit) Equal to Spell Breaker 0000 <gen>
Actions
Unit - Order (Killing unit) to Move To (Center of Unit Spawn <gen>)
[/trigger:1:56afc0c6fd]
when a unit dies, the game checks if it is true that the unit is an enemy of player 1 (red) and that it is the spell breaker that was targeted. if it is the unit is simply told to move back to the centre of the "unit spawn" region.
and there you have it, hopefully you have learn someting from this mini tutorial
try messing around with the triggers adding little things in and taking other things out, its amazing what you can do. after you have gotten the basics of triggers try using some variables, the "If / Then / Else" functions and the "for each integer x" loop actions. youll be well on your way to a fantastic map
Ps. report back on if this has helped you and how your project is progressing. if you need anymore help as away!
PPs. in future make sure you are more specific, the more specific you are the more we can help!
