Halo: The Master Chief Collection - Halo 2 - Inquisitive - Halo 2: Activate Terminal 2 on Outskirts. This achievement is fairly easy to unlock.
On the mission Outskirts, midway through the mission you will acquire a warthog to drive. Drive pas the majority of the enemies and you will have to drive over an obstacle with not much room from the watch.
After the obstacle to the left there is a small building. Hop out and inside the building is where the terminal is located against the wall.
Run over and interact with it and your achievement should pop! Enjoy!