Load up the level BLACK STATION
. I really recommend that you have already played trough this level as it can be somewhat confusing. This level can be very frustrating if you want to complete it full stealth as the checkpoints can be somewhat far apart. That is why the alternative cheese method here is recommended.
The achievement only states that you cannot kill or knock out any enemy. However getting spotted does not void the achievement. So breaking a leg from A to B as fast as possible is your easiest bet here.
At the start bring out your journal and follow your compass. I've linked a short video that uses the same cheese method to show the way:
The player in the video actually takes a detour but it is still pretty fast so there is nothing against taking the scenic route.