Spawning help please

All right im am making a small map were its 10 zerglings fight 10 ranged zerglings. i would like to know: how do u spawn a unit at region X after an X # of seceonds go by and "preserve" it? so give me some help people.

Edit: Oh btw how do i make it so a start location doesn't spawn units and buildings?

Have a look at this map I made quite a while ago, it may not direcly answer to your question. But at least it should give you a clue where to begin.

-U dun want start location spawn building then just delete floder intialization in trigger pannel then your map will change to custom map not a melee map
-U want two group of zerg appear at the same time then create 1 trigger like this
Event:map intial or whatever
Condition:none
Action:
-Create [number] unit type[type] for [player] at [region] ->copy and paste it and change region then u can make em create at different region at the same time and if u dont want that then use wait action
-Hope that can help u

i got it now. but i need to know how to set winning conditions once the other units are all killed

Edit: i don't know how do the winning conditions

-If u want all unit own by player got killed then make player win then it must relate to interger(or not but i cant find this condition),with your post i can figure u are newbie so if u want do all unit die make player win then make a trigger like this
+Create 1 variable interger no array i named it Unitcount
Event:A unit own by [player] die
Condition:Interger-Unitcount equal to 0
Action:
Game-Defeat [player]
Game-Victory [player]
-In your trigger spawn unit u must create an action like that
-Set Unitcount=[number of your unit spawn]
+Here the trigger subtract Unitcount
Event:A unit own by player die
Condition:Player owner of dying unit equal to [player]
Action:
-Set Unitcount=Unitcount-1
-Uhm i not good with english so if u dont see it then pm me or post back and i will give u a sample map ^_^

acutally i want it so that when either player 1 or player 2 has no units loses while the other player wins.

Edit: heres the map that needs im doing these triggers for. it is based on a sample scenerio in Warhammer 40k where 2 gaunts fight each other.