Round after round

[Gothok]

I want to do, that the first round starts, maybe 20 footmanfs were created. and what i want to do is: all footmans died, then i want a timer window top right which says "Next Level in 30 seconds" (counting down to 0) and on 0 the next wave comes, and so on... please help!

 

[Marc Mamales]

Here

• Creeps
  • Events
    • Time - Elapsed game time is 0.01 seconds
  • Conditions
  • Actions
    • Countdown Timer - Start Timer as a One-shot timer that will expire in 5.00 seconds
    • Countdown Timer - Create a timer window for (Last started timer) with title First Round Starts ...
    • Trigger - Turn off (This trigger)

• Creeps 2
  • Events
    • Time - Timer expires
  • Conditions
  • Actions
    • Unit - Create 20 Footman for Player 1 (Red) at (Center of (Playable map area)) facing Default building facing degrees
    • Wait until ((Number of units in (Units in (Playable map area))) Equal to 0), checking every 0.10 seconds
    • Countdown Timer - Start Timer as a One-shot timer that will expire in 30.00 seconds
    • Trigger - Turn off (This trigger)

• Creeps 3
  • Events
    • Time - Timer expires
  • Conditions
  • Actions
    • Unit - Create 20 Knight for Player 1 (Red) at (Center of (Playable map area)) facing Default building facing degrees
    • Wait until ((Number of units in (Units in (Playable map area))) Equal to 0), checking every 0.10 seconds