Subnautica

This achievement is for finding the enforcement platform. This is located on the island in the mountains biome. Eventually in the story you'll get a notification that the Sunbeam is going to land on this island and it will have a waypoint to help you find it.

The specific part of the facility that will get the achievement to pop is after you enter and start going towards the back near a terminal.

I also have made a video guide for the game with all of the achievements here.