Welcome to sc2mapster! Feel free to send me a PM if you need anything ;)
So you will want to make a variable to store your "special unit". You should have 2 variables- one for player 1's unit, and 1 for player 2's. Each of those variable should be "unit" variables.
Next, make a trigger. The event should be "unit dies". And then you would set the unit to your special unit for player 1. The events would be whatever you want to happen- like you could show a message saying "PLAYER 2 WINS!!". You would then make a 2nd trigger, but this one will have an event that runs when the 2nd unit dies.
I'm not sure how experienced you are- if you don't understand this feel free to send me a PM and I'll go into a more detailed explanation.

softshell1984 Regular ShmoeIve been making this map and i want to set the victory condition that you must kill the opposing players special unit. So when the special unit dies, your army looses the game. How do i set this condition and how do i set that special unit? sorry im kinda new at this.