If you want to do this the fastest method for just the 3 Wins, then do this:
Setup a Skirmish Match with these settings:
Game Type: Deathmatch
Fog of War: Off
Skull: AFTER PARTY(unlocked in mission 11, required for this method)
Any other helpful skulls can be turned on, put the AI on easy.
Don't forget to pick Colony as your leader..
As soon as the match starts, build on all the closest build points to the AI base, then self-destruct the bases in order to get a tank and infantry unit each time from the Skull.
Repeat this until your population is maxed.
Select all your units, move in, and wipe out the AI base! Use leader powers to help as necessary.Otherwise, if you want to get all 3 Colony DLC achievements at the same time: