Steps for this:
1. Go to the SMI and hit your left trigger
2. Choose COOP
3. If you have a friend you want to do this with then choose the Private Lobby option. If you want to roll the dice and try it with a random online choose Find Teammate.
4. Select any of the COOP Missions under Mission settings.
- The easiest is the first Briggs COOP only match. Put the difficulty on Rookie if you want and breeze through the level.
Note * After you have picked your level hit the B button to go back to start the mission
It took our team a while to figure out you need to hit B to go back to start the mission.
It would have been nice if UBIsoft had some on screen guide or way they could communicate that like maybe a red B button saying to go back and start the mission...
Anyway, pretty straight forward achievement.
Achievement will pop at the end of the mission.