How to do a Unit check?

[OrgeKings]

Im creating map a spawn map.
I need it to be able to check for builds.
Ex.
For every Gateway you own.
spawn 1 Zealot.
So if i own 1 gateway Spawn 1 Zealot.
If i own 2-3-4- spawn that many Zealots.
Can some one help please.

 

[Dan]

make use of a global integer variable!

trigger #1: whenever a building is constructed (that would be your trigger event) then add to +1 the variable (action).

trigger #2: spawns yourVariable units in spawnzone

 

[OrgeKings]

I know the editor decently but im just now starting to learn how to work the Variables more.
Can you please Explain how to do this alittle more?
I'm trying to make it similar to Desert Strike. Need the spawn system to be like that.
Please and thank you.