Halo: The Master Chief Collection - Halo 2 - Scholar - Halo 2: Activate Terminal 11 on Uprising. This achievement is fairly easy to unlock.
On the mission High Charity, later on in the mission you will be able to drive a ghost. Drive it all the way down the path which may take a little bit.
When you reach the end there will be a short drop down where you will then need to run up the path on the right to get on the structure. Run along the structure till you get to a clearing almost past it and turn into it then on your left the terminal will be against the wall.
Run over and interact with it and your achievement should pop! Enjoy!