Hello sherrylmc, what's your win condition?

by getting to the end of the map and after killing the zombies in front of the exit (surrounded by tons of villages of dooms)

note: and before the final swarm witch i forgot to mention

So there are my thoughts about that :

1) this a really tedious one but most realistic. Basically, on the tab where your place units/buildings etc, you can place a single zombie on the map. There, right click on the zombie and click on edit. Set its ID to 1 for example. Then repeat the same process but by adding +1. So second zombie ID will be 2, etc... Then you will have to go the event tab, create an event and in schedule column, write this condition : IsDead(1)&IsDead(2)&etc... (repeat the IsDead until you have all the numbers of the zombies.
Set the start time to zero.
Then, go to script, add an execute code, and in the execute rectangle, write EndGameWon()

2) instead of setting setting that condition, you can place a last vod behind the bubble of infected. There, right click on it a'd set its ID to 1. (basically life first option).

Do the exact same process as first option, but instead of adding a lot of IsDead, just put the first one as it concerns only one item in your map.

3) create an event, with the condition Count(ZombieWeakA)=0&Count(...). Basically, write Count(x)=0 (x is the type of the zombie), for all types of zombies. You can find their name variable in the tab "variables".

Once you have done that, go on script, create an execute code and again, write in the execute code section EndGameWon().

This option means that the player will if and ONLY if there is no zombie left on the map.

Events > New Event
Conditions Zxcode : Count(DoomVillage)=0 and Count(Infected)=0
Time Start 0D
Repeat Period 1D
go all the way to the bottom and check "is game won"