--------------Unit Help------------
Uhg...ok...up in the Scneario section(i suggest you dl Starcraft X-tra Editor, wonderul for new players...) and go to unit and hero settings, then u just use ur nice drop down menu, and check off the use defaults, then you can change names/attack...so on and so forth(within limits)...so play around with that, its very well orginized...uhh...specail units...go uptop to...where it says layer (terrain layer) and change to unit layer, or at left side the unit is there...check the dropdown section and basiaclly, same as unit changing, click on the unit u want, and place him...well wherever u want
-----------Trigger Help------------
Ok, this might be long....
Alrighty...they look like two gears in the top bar...your triggers, ok, basics...you can change things, most are pretty self explanitory (bring, accumatle, elapsed time)...but to explain ur question...3 minutes =180 seaconds...so bassiacly...
---Condintions ---(no i cant spell today, tired)
Elapsed Time Atleast 20 sec (thats random, u can use any time, or always)
---Actions---
Create Units(You're gunna want to make a specail location)
Create --Insert Unit Amount Here-- Of --Insert Unit Here-- At Location --Insert Location-- For Player 1(Default, you can change that to ur desire)
Wait 3 minutes (but its in milliseconds, so for your pleasure)
Wait 18000 Milliseconds (yes alot)
Preserve Trigger
---Example--- The - and - infront of/at the end of words mark user inputed
Create -10- -Zerg Hydralisks- At -I Like Creating- For -Player 6-
Wait 18000 milliseconds
Preserve Trigger
Thatl create 10 hydras at that loaction every 3 minutes, hope this helps! p/m me with any other questions