TD Creature Spawn help

hello, im working on a new td map and I am having trouble with the spawning triggers. if someone can help describe to me how to create an effective spawn please reply ... this is what i have but has been less then perfect-

the spawn-

Events
Player - Player 12 (Brown)'s Food used becomes Equal to 0.00

Conditions


Actions
Set Level = (Level + 1)
Wait 1.00 seconds
Unit - Create 15 Leveltype for Player 12 (Brown) at (Center of A <gen>) facing (Position of (Triggering unit))
Wait 1.00 seconds
Unit Group - Order (Units in A <gen>) to Move To (Center of B <gen>)


the creature type trigger-

Events
Player - Player 12 (Brown)'s Food used becomes Equal to 0.00
Conditions
Level Equal to 2
Actions
Set Leveltype = a creatue

then i wound do this trigger over and over again with a diffrent condition ie

Conditions
Level Equal to 3....

There's quite a bit on spawning etc around these forums if you do a search. I would suggest using an array for unit-types, called for example Creeps

Events
Player - Player 12 (Brown)'s Food used becomes Equal to 0.00

Conditions

Actions
Set Level = (Level + 1)
Wait 1.00 seconds
Unit - Create 15 Creeps[Level] for Player 12 (Brown) at (Center of A <gen>) facing (Position of (Triggering unit))
Wait 1.00 seconds
Unit Group - Order (Units in A <gen>) to Move To (Center of B <gen>)


Of course you'll need to set the array up with the unit-types of the creeps you want:

Events:
Map init

Conditions

Actions:
set Creeps[1] =
set Creeps[2] =

etc


There's heaps of other ways of doing it too, doing a search will probably reveal another possibly answer.

Thank you this will due wonderfully

ok im still having trouble, it seems to always skip one level of creeps. goes from level one to three three to five