Ok now, this trigger is setup to make the spawns for All of the levels of a td(maul)
You would set up a trigger called Startup Movement. That trigger would include things that make the units move around. (you don't need this trigger to setup spawning and all of that)
You would also set up a trigger called End Level. That trigger would be something like this:
Event-
Player - Player 12 (Brown)'s Food used becomes Less than or equal to 0.00
Condition-
Defeat Equal to False
Actions-
Set Level_Number = (Level_Number + 1)
[this is what changes what the Game - Display text]Countdown Timer - Start Next_Level with 30 seconds
Countdown Timer - Create a timer window for (Last started timer) with title ((Level + (String(Level_Number))) + in...)
[this makes it so players can see the timer]Trigger - Run Set Levels <gen> (checking conditions)
[Set Levels is the trigger I show you below](and mabey some other things)
Now that Countdown Timer action is what will trigger the spawns to take place. When the 30 seconds is over the timer is referred to as "expires." Now, you can look at the picture i gave u and you can see that the event is "Next_Level expires" so the trigger is set off and it checks the condition then does the actions.
Now you see the action that creates units. In that case it is just 1 spawn point, so you would need to make 2 more of those in a regular 3 spawn td(maul). The only difference between each one is the region would (obviously) change.
Now I know you are wondering how it knows what monsters to use etc. etc. Well, the Monster_Amount is basically useless, you should just put a number like 20 there. However, the Monster_Type matters! if it wasn't there then u would have to make like 30 of these triggers. The Monster_Type is setup using another trigger:
Event-
(There is no need for an event because the trigger I showed you above starts this)
Condition-
Defeat Equal to False
Actions-
If (Level_Number Equal to 1) then do (Set Monster_Type = Scout lvl 1) else do (Do nothing)
If (Level_Number Equal to 2) then do (Set Monster_Type = Engineer lvl 2) else do (Do nothing)
If (Level_Number Equal to 3) then do (Set Monster_Type = Night Ranger lvl 3) else do (Do nothing)
etc.
Here is a picture of what Monster_Type should be setup as:
By the way, nearly all of the pictures I put are clickable, which will bring it up much larger in a new window.
I hope that helps you more.. There are other triggers like tips and gold but I suggest you figure the spawning one out first..